THE ACQUISITION OF THE MORPHOSYNTAX OF FINITE VERBS IN ENGLISH* Andrew Radford, University of Essex (1991) 1. Theoretical Framework This paper is concerned with the acquisition of the morphosyntax of finite verbs by monolingual children acquiring British English as their first language. The primary data are drawn from a large naturalistic sample of more than 100,000 early child utterances (based on the corpus of 39 crosssectional and 94 longitudinal studies described in Radford 1990a, pp. 11-13). The theoretical framework used will be that of Government and Binding Theory (= GB), in the version outlined in Chomsky 1986, with modifications introduced by Abney 1987 and Pollock 1989. In order to clarify some of the descriptive assumptions made here, I shall begin by providing a brief outline of the morphosyntax of finite verbs in adult English. Following Pollock 1989, I shall assume that finite clauses are projections not only of the lexical category V, but also of the functional heads C (= complementizer), T (= Tense) and AGR (= Agreement), so that a typical clause in English would have the canonical superficial structure in (1) below: (1) CP C TP subject T' T AGRP AGR VP V complement (In accordance with the standard pruning convention, I have pruned any single-bar category which is an only child.) Modal auxiliaries like can would be base-generated in T, and thus inflect only for tense (cf. the past tense form could), not for agreement (cf. *'He cans speak French'); from T, modals can move into C by head-to-head movement, so resulting in inversion structures such as 'Can I help you?' The dummy auxiliary do would be base-generated in AGR, and thence move (by head-to-head movement) into T, so accounting for the fact that auxiliary do carries both tense and agreement inflections (cf. 'He really does/did appreciate your kindness'); from T, do _________________________________________________________________ *I am grateful to two anonymous reviewers for helpful comments on an earlier version of this paper. can then move to C, so yielding inversion structures such as 'Does/Did he appreciate it?' By contrast, the auxiliaries have/be are base-generated in V, and move (by successive applications of head-to-head movement) first to AGR and then to T, so that have/be also inflect both for tense and agreement; from T they can be raised to C, resulting in inversion structures such as 'Was he telling the truth?'. Clauses containing finite nonauxiliary verbs (e.g. 'He tells the truth') involve a null dummy auxiliary base-generated in AGR which raises to T, so forming a constituent in which an inflectional affix such as +s is attached to a null stem; in order to satisfy the requirement that affixes be attached to overt stems, the tense/agreement inflection (e.g. +s) is lowered from T onto the right of the head V of the VP (so resulting in an inflected verb form like tell+s). Because nonauxiliary verbs are superficially positioned in the head V of VP, they are prevented from undergoing inversion, since the empty category principle licenses movement to C only from a head position properly governed by C (i.e. only from T). Nonauxiliary verbs cannot move from V to AGR (and thence from to T and C) since AGR in English is insufficiently 'strong' to attract a nonauxiliary verb (in Pollock's framework, this is because AGR in English is opaque to theta-role transmission, so that e.g. a transitive verb which moved from V to AGR would not be able to theta-mark its complement). For further details of this analysis, the reader is referred to Pollock 1989. An additional assumption which I shall be making here is that only lexical categories (N, V, A, P) and their single-bar projections (N', V', A', P') can assign theta roles, and that theta-marking takes place under strict sisterhood. It follows from these assumptions that a constituent can only be theta-marked by a non-maximal lexical sister (i.e. by a sister constituent which is a lexical category but not a maximal projection). One consequence of this set of assumptions is that the subject of TP in (1) must be base-generated in the specifier of VP, in order to receive a compositional theta-role from its sister lexical constituent V-bar. The subject is ultimately raised into a nonthematic position as the specifier of TP in order that it can receive case. Similar assumptions are made in Hoekstra 1984, Koopman and Sportiche 1985, Kitagawa 1986, Kuroda 1987, Fassi Fehri 1988/1990, and elsewhere. There are two interesting characteristics of adult structures like (1) which are worthy of comment. Firstly, they comprise not only lexical categories (like N, V, A, P and their projections), but also functional categories (like C, T, AGR and their projections). Secondly, adult structures are networks of both thematic and nonthematic sisterhood relations, in the sense that any set of sister constituents may either be thematically related (where one of the sisters theta-marks the other/s), or thematically unrelated (where none of the sisters theta-marks the other/s): for example, V in (1) theta-marks its sister complement, whereas T-bar does not thetamark its subject specifier. We might therefore say that adult structures are sets of lexical and functional categories bound together by networks of thematic and nonthematic sisterhood relations. 2. Verbs in Early Child English Having provided a brief outline of the syntax of verbs in adult English, I now turn to consider the syntax of verbs in the earliest multiword speech produced by English-acquiring children. It is generally assumed that children first start to form productive syntactic structures during the period of early patterned speech which typically lasts from around 20 to 24 (+_20%) months of age (cf. e.g. Goodluck 1991): I shall refer to this period as early child English. In Radford 1990a, I argued that the syntactic structures found in early child English differ significantly from those found in adult English in two interesting and inter-related respects. Firstly, whereas adult sentences are projections of both lexical and functional heads alike, child sentence structures are projections of the four primary lexical heads (noun, verb, adjective, and preposition), and lack functional heads and their projections altogether. Secondly, whereas adult structures are networks of both thematic and nonthematic sisterhood relations, their child counterparts are pure networks of thematic relations (in the sense that every set of sister constituents is thematically related). Thus, all structures found in early child English are sets of lexical categories bound together by thematic sisterhood relations: we might therefore say that the earliest structures produced by English-acquiring children are lexical-thematic in nature. We can illustrate what this means in concrete terms by considering the structure of a typical child utterance such as 'Man drive car'. Given the lexical-thematic analysis of early child English proposed here, this would have the simplified structure (2) below: (2) VP NP <-------AGENT------- V' Man V -----PATIENT-----> NP drive car The whole structure would be a verb phrase (i.e. a verbal small clause): it would be a lexical structure in that it comprises only projections of the head lexical categories N and V. It would also be a thematic structure in the sense that the V drive theta-marks its sister NP constituent car (assigning it the role of PATIENT), the V-bar drive car theta-marks its sister NP constituent man (assigning it the role of AGENT), the NP car is theta-marked by its sister V drive, and the NP man is theta-marked by its sister V-bar drive car. The twin hypotheses that the earliest structures produced by English-acquiring children contain (i) lexical but not functional, and (ii) thematic but not nonthematic sister constituents will be closely inter-related if we follow Abney (1987: 54 ff.) in positing that the essential difference between lexical and functional categories lies in the fact that lexical categories have thematic content whereas functional categories do not. The hypothesis that early child sentences are purely lexical-thematic structures echoes earlier ideas in Radford 1986/1987/1988/1990a, Abney 1987 (p. 64), Guilfoyle and Noonan 1989, Lebeaux 1987/1988, Kazman 1988, and Platzack 1990. In Radford 1990b, I examined the implications of the lexical-thematic analysis for the morphosyntax of nominals in early child English, concluding that children use lexical NPs in contexts where adults require functional DPs or KPs. In this section, I examine the implications of the lexical-thematic analysis for the morphosyntax of finite verbs in child English. What I shall argue here is that the earliest verbal clauses produced by young children are lexical-thematic VPs like (2), and lack the further functional projections of VP into AGRP, TP and CP found in adult clause structures such as (1). Consider first the evidence in support of the claim that early child grammars of English have no T-system. Given that modals are base-generated in T in adult English, this leads us to expect that young children show no evidence of having developed a category of modal T constituents. Numerous published studies have commented on the systematic absence of modals as a salient characteristic of early child speech: cf. e.g. Brown 1973, Wells 1979, Hyams 1986, and Aldridge 1989. Indeed, this pattern was reported in studies of imitative speech in the 1960s. For example, Brown and Fraser 1963, Brown and Bellugi 1964 and Ervin-Tripp 1964 observed that children systematically omit modals when asked to repeat model sentences containing them, as illustrated by the following examples which they provide (ibid.): (3) (a) (b) (c) (d) ADULT MODEL SENTENCE Mr Miller will try I will read the book I can see a cow The doggy will bite CHILD'S IMITATION Miller try Read book See cow Doggy bite CHILD Susan 24 Eve 25 Eve 25 Adam (Here and elsewhere, we give the first name of the child who produced the relevant utterance, and the child's age in months, where known.) It seems reasonable to suppose that whereas the adult model sentences in (3) are functional-nonthematic TPs (contained within an abstract CP), their child counterparts are lexical-thematic VPs: for example, the adult model sentence in (3)(d) is a (CP containing a) TP of the simplified form (4)(a) below (where e denotes an empty category), whereas the child's imitation by contrast is a VP of the simplified form (4)(b): (4)(a) (b) [TP [DP The doggy] [T will] [AGRP [AGR e] [VP [V bite]]]] [VP [NP Doggy] [V bite]] The systematic differences between the adult model sentences and their child counterparts are directly predictable from our hypothesis that early child grammars lack functional/nonthematic constituents, so that in place of adult functional TPs children use lexical VPs. A second function of the T constituent in adult English is that it is the locus of tense inflections: non-modal auxiliaries acquire these inflections by moving into T, whereas nonauxiliary verbs acquire them by having the relevant inflections lowered from T to V. Thus, if children have no T-system at this stage, we predict that they will show no evidence of acquisition of the past tense inflection +d. Typical of children's speech output at this stage are the utterances produced by the children in the following dialogues: (5)(a) ADULT: CHILD: What did you draw? Hayley draw boat (Hayley 20) (b) ADULT: CHILD: What did you do in your new bed? Jem get in (Jem 21) The children's non-acquisition of tense inflections is illustrated by the fact that the children reply to a question containing an auxiliary did overtly marked for tense with a sentence containing an (italicized) tenseless verb. Moreover, traditional morpheme acquisition studies (e.g. De Villiers and De Villiers 1973, Brown 1973, Kuczaj 1977) provide further empirical support for the claim that children at this stage (roughly, under two years of age) make no productive use of tense inflections. But what evidence is there that children likewise have no AGR system? In the light of the claim in section 1 that the dummy auxiliary do is base-generated in AGR (and thence moves to T, whence it moves to C in direct questions), one prediction made by the lexical-thematic analysis of early child English is that there will be no use of dummy do (since this is an abstract functional constituent with no thematic content, whose sole role is to act as a carrier for tense and agreement inflections). In this connection, it is significant that in contexts where do (or some other auxiliary) would be obligatory in adult English, children make no use of do (or any other auxiliary). Typical in this respect are do-less negatives and interrogatives such as the following: (6)(a) (b) Kathryn no like celery. Man no go in there. Kathryn not go over here. Kathryn no fix this (Kathryn 22-24, from Bloom 1970) Jane go home? (Claire 24, from Hill 1983) The absence of the base-generated AGR auxiliary do in early child English is obviously consistent with the view that early child grammars have no AGR constituent. A second function of the AGR constituent in adult English is that it is the locus of agreement inflections: the auxiliaries have and be acquire these AGR inflections by moving from V into AGR, whereas nonauxiliary verbs acquire them by having the relevant AGR inflections lowered onto V. However, children show no productive use of the third person singular agreement inflection +s on verbs or auxiliaries at this stage, as the following dialogues illustrate: (7)(a) ADULT: CHILD: What does Ashley do? Ashley do pee...Ashley do poo (Jem 23) (b) ADULT: CHILD: What does the pig say? Pig say oink (Claire 25, from Hill 1983) Note that when asked a question containing an auxiliary overtly inflected for agreement, the children reply using an uninflected, agreementless verb (italicized); once again, traditional acquisition studies (e.g. Brown and Fraser 1963, Brown 1973, De Villiers and De Villiers 1973) paint a similar picture. Since the agreement inflection +s is a realization of properties of AGR, the fact that young children make no productive use of agreement inflections provides further evidence in support of our claim that they have not yet acquired AGR. It is perhaps useful to pinpoint the exact nature of the differences between agreement-marked verbs in adult English, and their agreementless counterparts in child English. Given the assumptions made here, the child's reply Pig say oink in (7)(b) would be a lexical VP with the simplified structure (8)(a) below, whereas its adult counterpart The pig says oink would be a functional (CP containing a) TP with the simplified superficial structure (8)(b) (where e denotes an empty category): (8)(a) (b) [VP [NP Pig] [V say] oink] [TP [DP The pig] [T e] [AGRP [AGR e] [VP [V says] oink]]] The differences between the two structures reflect the familiar pattern that adult clauses are functional-nonthematic structures, whereas their child counterparts are lexical-thematic structures. Thus, the overall clause has the status of a functional CP/TP/AGRP containing a lexical VP complement in adult English, but of a lexical VP in early child English; the verb says carries an +s inflection which encodes properties of both T and AGR in (9)(b), but the child's verb say in (8)(a) carries no T or AGR inflections for the obvious reason that the child's grammar has no T system or AGR system; the adult subject the pig is a functional DP which superficially occupies a functional nonthematic position (as the specifier of the functional category TP) in (8)(a), whereas its child counterpart is a lexical NP which superficially occupies a lexical thematic position (as the specifier of the lexical category VP) in (8)(b). Having argued that early child clauses lack a T system and an AGR system, I now turn to argue that early child clauses likewise lack the functional C system found in adult English ordinary clauses. Given that complementizers are nonthematic constituents which are basegenerated in a functional position (in the head C of CP), it follows that our lexical-thematic analysis would predict that early child clauses will contain no C system whatever. Some evidence which supports this conclusion comes from the fact that children's complement clauses at this stage are never introduced by overt complementizers like that/for/whether/if: on the contrary, children's complement clauses at this stage are purely lexical-thematic structures, as illustrated by the bracketed clausal complements of want in (9) below: (9)(a) (b) (c) Want [mummy come] (Jem 21) Want [lady get chocolate] (Daniel 23) Want [hat on]. Want [monkey on bed]. Want [coat on] (Daniel 23) Children's complement clauses at this stage resemble adult small clauses: the complement clause is never introduced by a complementizer – a fact which is clearly consistent with our view that early child clauses entirely lack a C system. Moreover, imitative speech data yield the same conclusion: Phinney (1981) notes that young children consistently omit complementizers on sentence repetition tasks. Given that a second role of the C-constituent in adult speech is to act as the landing-site for preposed auxiliaries (which are move into C, e.g. in direct questions), we should expect that children under two years of age will not show any productive examples of (subject-auxiliary) inversion in direct questions. In fact, early child interrogative clauses show no evidence whatever of auxiliaries preposed into C, and more generally lack auxiliaries altogether. Typical examples of auxiliariless interrogatives in early child speech are found in the transcripts of the speech of Claire at 24-25 months in Hill (1983), where we find questions such as the following: (10) Chair go? Kitty go? Car go? Jane go home? Mommy gone? As Klima and Bellugi remark (1966: 201) it is characteristic of early child English at this stage that: 'There are no auxiliaries, and there is no form of subject-verb inversion'. Once again, the absence of preposed auxiliaries is consistent with our hypothesis that early child clauses lack a syntactic C system (given that preposed auxiliaries are positioned in C): cf. similar conclusions reached in Radford 1986/1987/1988/1990a, and echoed in Guilfoyle and Noonan 1989. Not surprisingly, we also find that because children's clauses lack a C system at this stage, they also lack a specifier of C, so that young children are unable to parse or produce structures involving unbounded wh-movement (since this involves movement of a wh-phrase out of an underlying thematic position into a nonthematic position as the specifier of a functional C-bar constituent): cf. Radford 1990a (chapter 5) for detailed exemplification and discussion. The overall conclusion to be drawn from our discussion here is that the earliest verbal structures found in early child English are lexical-thematic projections of V into VP, and lack the further functional-nonthematic projections of VP into AGRP, TP and CP found in adult English. From this, it follows (inter alia) that there will be no V-movement operations of any kind found in early child English. In adult English, we find three kinds of head-movement operation affecting verbs. One is movement from T to C (as with modal inversion in structures such as 'Can he cook?'); a second is movement from AGR to T (as with dummy do in 'He really does like you'); a third is movement from V to AGR (and thence to T), as with the auxiliaries have/be in 'He has done it/He is doing it'. In all three cases, the moved head moves into a functional head position (viz. into AGR, or into T, or into C). But if the earliest structures produced by young children are purely lexical in nature, then it follows that early child grammars will entirely lack functional heads, and therefore cannot in principle license any head-to-head movement operation involving movement to a functional head. Thus, the absence of V-movement in early child English follows from the absence of functional heads in early child grammars of English. 3. Explanation and Prediction Given that the ultimate goal of linguistic theory is to attain explanatory adequacy, an important question to ask at this point is why early child grammars of English should lack functional heads (i.e. functors) and their projections. This is a question which we explore briefly in this section. There are a number of traditional explanations offered in the literature for why functors are lateacquired. Many of these seem problematic in a variety of ways. For example, the suggestion by Gleitman and Wanner (1982) that functors are late acquired because of perceptual problems posed by their lack of phonological salience raises the question of why (in my corpus) unstressed clitic auxiliaries in English are acquired before their more salient nonclitic counterparts (e.g. why 's and 'll are acquired before the full forms is and will), and why the (phonetically insubstantial and morphophonologically variable) plural +s suffix should be used productively from around 20 months of age. Likewise, any suggestion that functors are acquired later than contentives because of their greater morphosyntactic irregularity (e.g. the Auxiliary may is acquired later than the verb play because it has the irregular past tense form might) is called into question by the fact that irregularity as such seems to pose no barrier to acquisition, since children typically regularize irregular forms, so that a verb like see will be given an overgeneralized past tense form seed. Moreover, intuitively plausible cognitive explanations to the effect that functors are cognitively more complex than contentives (and so cannot be acquired until the child has reached a certain level of cognitive maturity) pose the problem that there is no objective way of determining the relative cognitive complexity of different items, and no reliable language-independent means of determining the child's cognitive capacity at any given stage of development (as noted by Atkinson 1982). Given obvious drawbacks to traditional explanations, we might explore alternative possibilities. One possibility would be to suggest that parameter theory might yield an explanation. More specifically, we might suppose that languages vary parametrically with respect to the range of functional categories which their grammars utilize: for example, if Fukui (1986) is right in the claims he makes about Japanese, then Japanese would differ from English in having no C system, AGR system, or D system. Chomsky (1989) has suggested that all parametrization in grammars may be located in their functional category systems: this is generally referred to as the functional parametrization hypothesis. If this is so, then it would seem reasonable to suggest that lexical category systems develop first because their properties are determined by innate (nonparametrized) principles of UG, and that functional category systems are acquired later because considerable linguistic experience is required in order for the child to set the functionality parameters which determine the range and nature of functional category systems. Thus, we might suppose that the functional parametrization hypothesis predicts that lexical heads will generally be acquired before functional heads – and this is clearly consistent with the pattern of development described in the previous section. A further type of explanation which we might consider is a maturational one, to the effect that different linguistic principles are genetically programmed to come into operation at different stages of maturation (cf. e.g. Borer and Wexler 1987, and Cinque 1988). We might conjecture that the principles which enable children to form lexical-thematic structures come 'on line' at around the age of 20 months (+_20%), coinciding with the phenomenon of vocabulary spurt described in Smith 1926, Benedict 1979, and McCune-Nicolich 1981. We might also suppose that the principles which enable the child to form functional-nonthematic structures come on line at around the age of 24 months (+_20%), coinciding with the syntax spurt described in Anisfeld 1984: 129-30. As we have seen, both the functional parametrization hypothesis and the maturational hypothesis would account for the pattern of development observed in the previous section, in which lexical heads are acquired before functional heads. An obvious question to ask, therefore, is what each hypothesis predicts about the relative order of acquisition of the three different functional heads (T, AGR and C) which concern us here. It seems likely that there is nothing in either hypothesis which directly predicts the pattern of development when children reach the functional stage of development. Both hypotheses would have to posit that external factors determine the relative order of acquisition of functors. One such factor which might be involved in the nature of the child's experience: for example, Newport, Gleitman and Gleitman (1977) and Wells (1985) claim that the acquisition of auxiliaries is directly correlated with the frequency of yes-no questions in the speech input which children receive from their caretakers. Within the framework we are using here, we might reinterpret this claim as implying that the development of the child's T system depends on the frequency with which the child encounters inverted auxiliaries in C (for the obvious reason that one of the principal criteria for determining whether a given item is positioned in T or in V is whether or not it can undergo inversion to C). If this is so, it might lead us to expect that the T system and C system are acquired more or less simultaneously. A second external factor which might determine the relative order of acquisition of functors and is their relative complexity. However, an obvious problem here is that there is no objective way of determining whether (e.g.) the tense properties encoded in T are substantially more complex than the agreement properties encoded in AGR or than the illocutionary properties encoded in C (by virtue of the fact that whether is an interrogative C and that noninterrogative, or that 'Can I help you?' is interrogative whereas 'I can help you' is declarative). However, given that English is a language in which finite forms have a highly impoverished inflectional morphology (so that T and AGR have relatively simple morphological realizations, and C has no overt morphological realization save in the first person negative interrogative form aren't I?), there is no obvious reason to suppose that T, AGR and C should not be acquired more or less at the same stage of development. The obvious question to ask at this point is whether this is the case. Using evidence from a large naturalistic corpus of children acquiring English as their first language, Aldridge (1989) argues that tense and agreement affixes, modal and dummy auxiliaries, and auxiliary inversion are all acquired at the same stage of development (typically shortly after children reach two years of age). In Radford 1990a, pp. 278-288, I present extensive data from a dozen different children aged 26 or 27 months to show that they have all acquired a fully developed set of functional category systems (including not only a C-system, T-system and AGR-system in clauses, but also a parallel D-system and K-system in nominals). For the sake of brevity, I shall present data from only one child here, relating to the acquisition of T, AGR and C; the examples given below are a small sample of the relevant utterances produced by Heather at age 26 months in a single 45-minute recording: (11) I'll have that one, shall I? I'll be sick soon. Shall I close it? I can. You can't get me. Can I have it? I couldn't know. That one might be called Dick. It might not. Would you like a sweetie? I don't want my slippers. I do laugh! We do! That does. Don't get my trousers on, will you! Did you want that one? Do you like that one? I'm opening that. And then we're going shopping. This is my left hand. He's smacking her, isn't he? They're my little dollies, aren't they? There are some sweeties in there. When I was a little baby. Is her cradle in there? Are we going on an aeroplane now? Isn't he beautiful? Wasn't that a shame? I've never seen one like that. I've got some new shoes. Matthew has left his duck behind. He has to leave it there now. Have you got one? I haven't. Alice, where are you? What's she saying? What's she doing? What's he got? What did he do? What have you got? What's his name? I tipped them all in there. And he left his car behind. I did it. I've given those to Daddy, for when he comes back. Wait till that starts. It tastes nice. These examples show evidence of well-developed T, AGR and C systems. Modals are intrinsically finite, inflect for tense (cf. past tense forms like might and would) and undergo inversion in questions, and thus seem to be base-generated in T (whence they can move to C in questions). Dummy do is intrinsically finite, inflects for both tense (cf. did) and agreement (cf. does), and undergoes inversion; hence we might suppose that it is base-generated in AGR, whence it moves to T in declaratives, and thence to C in interrogatives. Have and be have nonfinite forms (a property of V constituents), and also have finite forms which inflect for tense/agreement and undergo inversion in questions; it might therefore seem plausible to suppose that have/be originate in V, and move from there to AGR and to T in declaratives, and thence to C in interrogatives. What makes it all the more plausible to suppose that inverted Auxiliaries are superficially positioned in C is the fact that preposed wh-phrases (like those in the examples above) are positioned to the left of the inverted auxiliary, exactly as we would expect if inverted auxiliaries were in the head C position of CP, and preposed wh-phrases in the specifier position of CP. Thus, it would seem as if Heather has already mastered the morphosyntax of English auxiliaries. As far as nonauxiliary verbs are concerned, it seems likely that (as in adult English) they are base-generated in the head V position of a VP which serves as the complement of a null dummy auxiliary in AGR; the dummy auxiliary is raised from AGR to T, and the resulting tense/agreement affix is then lowered onto the right of the head V of VP. Since nonauxiliary verbs remain in the head V position of VP and are never raised from V to AGR to T, they are prevented (by the empty category principle, ECP) from undergoing inversion (since ECP licenses movement to C only from T) – hence the fact that nonauxiliary verbs do not undergo inversion. Some empirical support for the claim that nonauxiliary verbs function as the complement of an abstract dummy auxiliary (a null counterpart of do) comes from the fact that they are tagged by the dummy auxiliary do, as the following examples (produced by a variety of different children) illustrate: (12)(a) (b) (c) (d) (e) (f) I see Timmy, I do. I see Granny, I do. You muddle it up, you do (Robert 26) That one goes there, and Teddy does (Holly 24) She stinks, don't she? (Penny 42) Nonny had a drink, he did (Natalia 26) They put the car in that, didn't they Mum? I had it, I did (Christine 31) I won, didn't I? (Richard 36) Likewise, nonauxiliary verbs form negatives and direct questions with do support, as the data in (11) illustrate. I assume, therefore, that nonauxiliary verbs have essentially the same morphosyntax as in adult English. If this analysis is along the right lines, then it seems that we have evidence that by the tender age of 26 months, children like Heather have acquired the essentials of the adult T, AGR and C systems. What is particularly interesting in the context of the question we asked earlier about the order of acquisition of functional heads is that these three different functors (T, AGR and C) seem to have been acquired together. This is clearly consistent with both the functional parametrization hypothesis and with the maturational hypothesis, though (for the reasons outlined earlier) is in one sense directly predicted by neither. 4. Miscategorization As we saw in section 1, there are four different head positions which auxiliaries can occupy in adult English; modals are base-generated in T, and can move to C; dummy do is base generated in AGR, and obligatorily moves to T, whence it can move to C; be and perfective have originate in V, and obligatorily move through AGR into T, whence they can move into C; transitive have is obligatorily positioned in V in American English, but can optionally move from V to T (through AGR) in British English (whence it can further move to C). Given the mobility of auxiliaries in British English, it is scarcely surprising that children sometimes miscategorize auxiliaries, and misanalyse them as base-generated in a different position from that in which they originate in adult English. The most complex of all auxiliaries in British English is have, so it is not surprising that children seem to simplify its categorization. They treat transitive have as a nonauxiliary verb which has nonfinite forms and takes do support: cf. (13)(a) (b) (c) (d) (e) (f) (g) (h) (i) (j) Can I have this one? (Holly 24) Let's have him. Let's have them (Lucy 24) Jem want to have the lovely boat. Please may I have Ribena juice? (Jem 26) Baby's having some (Helen 24) I'm having this (Rebecca 26) I've had a lunch (Joanna 38) You've had it, haven't you? (Jonathan 39) I had it, I did. You don't have it (Christine 31) He had a rabbit, he did (Kelly 36) It doesn't have legs, does it? (Emma 37) In spite of the fact that transitive have can function as an auxiliary in British English, there is not a single example of this usage in my corpus. In its use as an aspectual auxiliary, by contrast, have functions solely as an auxiliary (like its adult counterpart), and so is used without do support: (14)(a) (b) (c) (d) (e) We haven't got Spiderman. No, we haven't got one (Robert 26) But we haven't got one now (Christine 31) P'rhaps he hasn't got a bed (Helen 31) You've had it, haven't you? (Jonathan 39) Christopher hasn't been in countries before, has he? What sort of beak have they got? (Matthew 41) But where there is an apparent difference with adult English is that two- and three-year-olds generally use perfective have exclusively in finite forms. This might account for the observation made by Major (1974) that even much older children achieve very low success rates with nonfinite forms of have on sentence repetition tasks: her research showed (inter alia) that 90% of her six-year-old subjects could correctly repeat will read, but only 30% will have talked; 100% could correctly imitate going to watch, but only 20% going to have stayed; 80% could successfully imitate ought to share, but only 10% ought to have worn. Such data suggest that two-year olds treat aspectual have as an auxiliary base-generated in AGR and raised to T (so that aspectual have inflects for both tense and agreement), whence it can undergo inversion to C. Thus, I conclude that two-year olds generally categorize transitive have as a nonauxiliary verb, and aspectual have as an auxiliary base-generated under AGR. Some children, however, seem to treat have as an auxiliary which does not inflect for agreement: cf. (15)(a) (b) (c) Mummy haven't finished yet, have she? (Olivia 36) No, she haven't (Ellen 39) He haven't got to do it, have he? (Olivia 42) The same is sometimes true of dummy do as well: cf. (16)(a) (b) (c) (d) (e) (f) That do go "Woo woo woo" (Olivia 30) He bite me, he do (Tony 27) He do! (Neil 33, in contradiction of 'He don't') How do he go? Do it live in a windmill? (Richard 36) Suzy goes out for a wee, Suzy do. She wees in the house, she do (Louise 44) She do! (Ellen 39, in response to 'She don't live up this street any more') The absence of the third person singular +s inflection on the italicised auxiliaries in (15) and (16) suggests that they are miscategorized as modals base-generated under a finite T (hence lacking the third person +s agreement affix). In the case of dummy do, this categorization may be induced by the occurrence of the agreementless third person present negative form don't in nonstandard forms of English (e.g. 'She don't love me no more'). What, then, of the auxiliary be? In all uses (e.g. its copula, progressive, and passive uses), this seems to behave very much like adult be. It has the nonfinite forms be/been/being (suggesting that it is base-generated in V): cf. (17)(a) (b) (c) (d) (e) (f) (g) (h) (i) I'll be sick soon. That one might be called Dick. And that might be called Helen (Heather 26) That might be Henry. It might be (Jimmy 35) Where've you been? Ben, where've you been hiding today? (Holly 24) I've been playing all the day (Helen 26) Cos he's been screaming (Andrew 32) This dolly's been sick (Lisa 34) They have been milked (James 40) When it's being done (Stephen 32) Remember, you are being the girl (Ellen 42) The fact that (as illustrated by examples like (11)), be forms negatives, direct questions, and tags without do-support suggests that it raises from V to AGR to T. However, for a handful of children, copula be seems to behave rather differently: cf. (18)(a) (b) (c) Do you be grey? (Rebecca 31) I don't be cheeky, do I? (Ellen 42) When me Nanny bes home. They all be on a bus (Olivia 36) Examples like (18) might be interpreted as suggesting that some children miscategorize copula be as a nonauxiliary verb which takes do support, and which forms its present tense by addition to the stem form be of the regular tense/agreement affixes used with nonauxiliary verbs. Utterances like (18) provide us with examples of an adult auxiliary being miscategorized as a nonauxiliary verb. The converse phenomenon (of children miscategorizing nonauxiliary verbs as auxiliaries) is equally rare: but note the observation by Erreich et al. (1980: 163) that a child identified as 'N' produced the following inverted use of go at age 23 months: (19) Goes paci in mouth? (N 23) (Eirreich et al. claim that N fronted no other nonauxiliary verbs). My own corpus reveals a potentially similar example: (20) Where go things? (Ellen 30) One possibility is that examples such as (19) and (20) are a result of children treating story-book sentences such as 'There goes the train!' as instances of the V2 phenomenon, and hence concluding that go must raise from V to AGR to T to C. Alternatively (but less plausibly), such sentences may be modelled on the (fossilized) adult greeting 'How goes it?'. Given that inverted auxiliaries occupy the head C position of CP in S-structure, we might expect to find that some children miscategorise inverted auxiliaries as base-generated C constituents. There have been a number of reports in the literature of children who were claimed to have used auxiliaries in inverted presubject position before they use them in uninverted postsubject position: cf. e.g. Gruber 1967, Cazden 1972, Miller and Ervin-Tripp 1973, and Wells 1979. If this is so, then these might be examples of children miscategorizing the relevant Auxiliaries as base-generated in C (We shall examine one type of structure which can plausibly be analyzed in these terms in section 6 below). 5. Null auxiliaries Miscategorization of auxiliaries (as illustrated in the previous section) is comparatively rare in child English. By contrast, an extremely frequent phenomenon is that Auxiliaries which must generally be overt in adult English can be null in child English. In this respect, child English seems to resemble Black English (= BE), since in BE specific forms of be have null variants (so that we find null allomorphs of are and is in contexts where standard English would require the contracted allomorphs 's and 're), as we see from BE examples such as the following (from Labov 1969: 717): (21)(a) (b) (c) (d) He fast in everything he do He just feel like he gettin' cripple up from arthritis You out the game We on tape Evidence in support of the assumption that such BE sentences incorporate a null allomorph of is/are comes from the fact that the 'missing' copula may surface in a tag, as in sentences such as: (22) He gonna be there, I know he is (Fasold 1980: 29) Interestingly, the form am (contracted to 'm) has no null counterpart in BE, nor do the past tense forms was/were. It would seem, therefore, that only the finite forms of be which have a null counterpart in BE are the specific auxiliary forms are and is. No less interestingly, Wolfram (1971: 149) reports that in nonstandard southern white English the only finite form of be with a null counterpart is are, not is (He notes that 'We normally get They nice but not He nice'; cf. the parallel observation by Fasold 1980: 30 that 'There are many southern whites who delete only are.'). It would seem, therefore, that in nonstandard varieties of adult English, specific auxiliary forms can be null. In child English, we find that not only the 're and 's forms of be can be null, but also 'm, as suggested by alternations such as the following: (23)(a) (b) (c) (d) (e) (f) It not blue. It's not yellow (Holly 24) That Victoria. Is that Victoria? (Hannah 26) He sleeping. He's sleeping (Alistair 30) I teasing Mummy. I'm teasing Mummy (Holly 24) I having this. I'm having 'nana (Olivia 27) You big bully, too. You're a big bully. They black tree. Are they black trees? (Holly 24) Moreover, have/has (when functioning as an aspectual auxiliary, though not in other uses) can also be null, as suggested by sentence pairs such as the following: (24)(a) (b) (c) (d) (e) We been there. We've been there (Robert 26) I given those to Daddy. I've given those to Daddy for when he comes back (Heather 26) I got this. I've got this (Jonathan 33) I not got that. I've not got that (Tony 36) Daddy gone. He's gone (Neil 24) (This is particularly common where the complement is headed by got/gone/been). There is also one example of a nonfinite form of have being null in my corpus, viz. (25) I might taken it off (Lee 36) In addition, it would seem that modals (particularly will) and the dummy auxiliary do also have null variants: cf. (26)(a) (b) (c) (d) (e) (f) (g) Mummy fix this. Mummy'll fix this (Holly 24) I get it. I will get it (Angela 25) I expect it be the square window. I expect it'll be the square window, I said (Neil 42) I eat you all up. I'll eat you all up (Hannah 32) That go there. Will that go there, look? (Hannah 27) I find it. I can find it, Mummy (Nancy 39) That dress not fit me. That dress doesn't fit me (Betty 33) There are several pieces of evidence which suggest that the auxiliariless sentences in (23-26) have a null allomorph of the italicized auxiliary in the head T position of TP at S-structure. The first is the fact that the auxiliary shows up in the second member of the pair in each of the paired sets of examples. The second is that we need to posit a null auxiliary in T in order to account for the fact that in structures like (24)(a) 'We been there' the copula been cannot undergo inversion (hence we don't find *'Been we there?', but rather 'Have we been there?'). Similarly, given that the negation patterns found in child English suggest that the NEG constituent not is basegenerated as the head of a NEGP constituent which serves as the complement of T, then auxiliariless negative sentences like those in (27) below: (27)(a) (b) (c) (d) (e) (f) (g) (h) (i) I not wet (Olivia 27) Mummy not like it (Samantha 27) He not got a hat on (Darren 30) She tried, and she not be a friend And he not taking that away (Andrew 32) That not go on there (Robert 33) I not going today (Olivia 36) Cos I not got much (Neil 39) Mummy not have tea (Sheila 42) suggest that there must be a null auxiliary in T preceding the negative not (Note that we could not analyse not as an invariable modal auxiliary like must since it never undergoes inversion, and is not always followed by an infinitive complement). Moreover, we need to posit a null auxiliary in order to account for the morphological form of the following verb: e.g. since a form like gone is used to head a VP complement of the perfective auxiliary have, the occurrence of gone in sentences like 'Daddy gone' in (24)(e) suggests the presence of a null variant of have determining the morphological form of gone. In addition, auxiliariless sentences in child English assign nominative case to their subjects (hence the use of the nominative pronouns I/he/we/they in sentences like (23-27)), and if we posit that nominative case is assigned by a finite T, then auxiliariless clauses must contain a null T constituent to assign nominative case to the subject. Finally, the null auxiliary may surface in an overt form in tag sentences such as: (28)(a) (b) (c) (d) (e) (f) (g) (h) (i) (j) (k) I on it, aren't I? (Sarah 26) I on this one, aren't I? (Elizabeth 26) Those steps, those are (Alistair 30) Cos they all hided, aren't they? (Christine 31) It dirty, is it? (Tony 30) That a new one, is it? (Neil 42) That nice and warm now, that is (Hannah 31) We done those two, haven't we? It got water on now, hasn't it? We have to use something else, won't we? We put it just there, won't we? (Matthew 39) So we have to use something else, won't we? (Per 41) He make me cry, won't he? (Anna 44) I do it, I can (Lisa 34) Thus, it would seem as if child English is a null auxiliary language – i.e. a language which allows (a wide range of) auxiliary constituents to have a null realization. More generally still, we might argue that child English is a null functor language – i.e. a language in which (a variety of) unstressed functors which would have reduced forms in adult English can have null forms (so that e.g. children who have acquired a wide range of determiners may nonetheless use a null determiner in a context where adults require an overt determiner, e.g. with a following count nominal in a sentence such as 'Can I have biscuit?'). The suggestion that child English licenses null functors in unstressed positions might be said to be implicit in Brown 1968. The null auxiliary analysis of child English opens up the possibility of providing an interesting account of the fact that children who show clear evidence of having acquired the tense/agreement affixes +d/+s sometimes appear to omit these affixes: for instance, go in the following examples seems to lack the third person singular affix +s: (29)(a) (b) (c) (d) (e) (f) (g) (h) (i) (j) (k) Think he go in the hole (Michael 24) It go down here (Adam 26) It go there (Sarah 26) That one go there. And this go in there (Rebecca 26) That go there (Hannah 28; Matthew 30) It go like that, yeah? (Michelle 29) This go backwards (Alistair 30) It go round and round (Helen 31) No, it go downstairs (Christine 31) This one go there (Kirsty 33) That go in car (Robert 33) (It should be noted that this phenomenon is found with nonauxiliary verbs in general, not just with go). One way of interpreting such data is to claim that sentences like (29) contain a null modal (e.g. a null counterpart of will) or null dummy auxiliary (i.e. a null counterpart of dummy do), and that this null auxiliary (like modals and dummy do in adult English) selects a complement headed by a verb like go in the infinitive (base) form. Some empirical support for this suggestion comes from sentence pairs such as the following: (30)(a) (b) (c) (d) (e) (f) That go there. Will that go there, look? (Hannah 27) Mummy fix this. Mummy'll fix this (Holly 24) That go there. That does go there (Hannah 30) He play with Laura, he does. Dolly fall over, Dolly does (Laura 32) He bite me, he do (Tony 27) Joan give it to you, didn't he Ma? (Penny 27) The fact that will/do appears in the second member of each pair of sentences makes it all the more plausible to posit a null variant of will/do in the first member. Aldridge (1989: 151) reports a related phenomenon. She claims that some two-year-olds attach tense and agreement affixes only to auxiliaries, and not to nonauxiliary verbs: among the data she cites in support of her claim are the following utterances produced by Katy at aged 28 months: (31) AUXILIARIES What's that? That's a box There it is I'm breaking it I'm eat them I'm walking it She's gone Where's she gone? Does that go? NONAUXILIARY VERBS She come back in a minute He drive a lorry She hide in the pudding She go to Pauline's She go back She go to the park He push me It go off Go fly One way of analysing the relevant data is to posit that such children's grammars do not license affix lowering, so that only items which are positioned in T and AGR at some stage of derivation (i.e. only auxiliaries) can acquire the relevant tense/agreement affixes. Nonauxiliary verbs would remain in V and always have their morphological form determined by the selectional properties of a higher auxiliary: in the case of sentences like those in the righthand column in (31), the auxiliary would be a null modal or a null counterpart of do, which would select a complement headed by a verb in the infinitive form. The null auxiliary phenomenon is also found in inversion structures. For example, null auxiliaries occur very frequently in wh-question structures such as the following: (32)(a) (b) (c) (d) (e) (f) (g) (h) (i) (j) (k) Why you got your eyes shut? Why have you got it shut? (Tony 27) What they done? What have they done? (Knox 42) Where horse gone? Where's Daddy gone, Mummy? (Tony 30) What he doing? What's he doing, Mum? (Jimmy 35) What you doing? What are you doing? (Penny 24) What you doing down there? What are you doing right down there? (Neil 39) Where that go? Where does that one go? (Laura 32) What you say `Thank you' for? What d'you say 'Ow ow ow' for? (Jonathan 33) Where you put that? Where d'you put that, Mum? (Darren 39) What the little boy do? What did he do next? (Frances 42) What I do? What shall I do? (Anna 44) It may well be that children's use of null auxiliaries in this type of structure is an overextension of a phenomenon found in rapid speech styles in colloquial adult English whereby a contracted auxiliary is seemingly replaced by a null auxiliary (symbolised by ø) in wh-questions such as: (33)(a) What d'/ø you do? (= do/did) (b) What 're/ø you doing? (= are) (c) What 've/ø you done? (= have) (In each case, the sequence What you could be realized as Whatcha.) Likewise, it is possible that the occurrence of null auxiliaries in declaratives like (23-28) in child English may be a further overextension of the pattern found in interrogatives like (33). It is not implausible that children misperceive adult unstressed contracted auxiliaries as null forms because of their lack of perceptual salience (cf. the related claim in Gleitman and Wanner 1982 that items with relatively low acoustic salience pose learning problems for the child). 6. Auxiliary Inversion I have assumed in my discussion hitherto that auxiliary inversion in child English (as in adult English) involves movement of a finite auxiliary from T to C. However, such an analysis of inversion in two-year-old English is by no means uncontroversial. For example, the assumption that inverted auxiliaries are positioned in C might seem to be called into question by the observation in Radford 1987 that inverted auxiliaries seem to be acquired several months before overt complementizers. Inverted auxiliaries typically become productive around the age of 24 months; however, complementizers appear a few months later, as examples such as the following illustrate: (34)(a) (b) (c) (d) See if swimming water's there (Jem 27) I dunno whether that frighten me (Ruth 30) You know that the flute is in there (Hannah 31) Leave a little space for them to get out (Helen 31) At this point, we may start to find other items being miscategorized as complementizers, so that children create novel complementizers of their own: for example, the following child seems to replace the adult prepositional complementizer for by the preposition in: (35) Don't wait in me go on it (Ruth 30; used twice, in separate, unchained utterances) Moreover, many children at around this age use cos (= because) to introduce main clauses, in such a way that it seems to have no causal force but appears to serve simply to mark the sentence as declarative in illocutionary force: cf. e.g. (36)(a) (b) (c) Cos that is mine (Hannah 28) Cos I can't reach the Ribena (Kirsty 33) Cos I didn't find it. Cos I brought her back. Cos it's in the freezer. Cos it's not ready yet. Cos we don't want to go in the kitchen. Cos I don't like this room. Cos I want her (Lisa 34) This might suggest that cos is used as a main clause declarative complementizer by the children concerned. Perhaps the most intriguing example of a novel complementizer created by young children is that noted by Akmajian and Heny (1975: 17) who report an unnamed three-year-old girl producing interrogative structures such as: (37) Is I can do that? Is you should eat the apple? Is Ben did go? Is the apple juice won't spill? Given that child English is a null auxiliary language, the declarative/interrogative contrast for the child is likely to be as in (38) below: (38)(a) (b) Daddy watching television (null Auxiliary declarative) Is Daddy watching television? (interrogative) It is understandable that on the basis of such as contrast, the child might miscategorize is as a yesno question complementizer. If it is indeed a general fact about acquisition (rather than an artefact of inadequate child data bases) that inverted auxiliaries are acquired before complementizers, then this might seem to challenge the plausibility of the analysis of early inversion as movement from T to C, and encourage us to explore alternative analyses of early auxiliary inversion. For example, we might suggest that there is an early stage in the acquisition of functional categories at which children have a T system and an AGR system but no C system, and that the interrogativity properties of the adult C system are carried in the child's T system (e.g. as features on the head T of TP); we might further suppose that an interrogative finite T assigns case to the right (to a subject in the specifier position of AGRP), whereas a declarative finite T assigns case to the left (to a subject in the specifier position of TP). If (as claimed by Cazden 1972, and Miller and Ervin-Tripp 1973) some two-year-olds restrict specific modals like can/will/could to interrogative use, then we could posit that such items are base-generated only under an interrogative finite T (and so will occur only in inversion structures). However, it is not clear to me what advantages such a TP analysis of inversion would offer over the conventional CP analysis; and clearly, the TP analysis would carry with it two major disadvantages. Firstly, it would require us to posit an asymmetry in the directionality of nominative case assignment (to the left in declarative finite clauses, but to the right in interrogative finite clauses). Secondly, it would require us to posit a major restructuring of the child's grammar at a later point, when the child has to 'delearn' the TP analysis and 'learn' the CP analysis (otherwise, we should wrongly predict that once children start to use complementizers, they will produce sentences such as *'I wonder whether will Father Christmas bring me a new car'). It seems to me that the standard analysis of inversion as movement from T to an empty C position is no more abstract and implausible for child English than for adult English: after all, inversion in adult English similarly applies only in clauses which do not contain an overt complementizer. Moreover, the analysis of auxiliary inversion in child English as movement from T to C can be motivated on theoretical grounds. Given the assumption that the only head-movement operations licensed by Universal Grammar are those in which one head moves to another head position, it follows that a preposed head T constituent can only be moved to another head position (and not e.g. adjoined to TP). Moreover, the empty category principle requires the moved head to properly govern its trace, so that a preposed T constituent can only be moved into an immediately superordinate head position like C from which it can properly govern its trace in T. If we follow Abney (1987) in positing that functional heads universally select a unique complement, and if we follow Pollock (1989) in positing that that C selects a TP complement, then it follows that the only head constituent which an inverted T can be adjoined to is C. What makes the T-to-C analysis all the more plausible is the fact that (as in the CP analysis of adult English) preposed wh-phrases are positioned to the left of preposed auxiliaries in children's direct wh-questions, as the relevant data in (11) and (32) illustrate. Moreover, child data such as (37) above (suggesting that children may miscategorize a preposed auxiliary as a complementizer) make it all the more plausible to posit that inverted auxiliaries are superficially positioned in T. Although I have suggested here that inversion in child English should be analysed as involving essentially the same T-to-C movement operation as in adult English, this is not to say that children use inversion in precisely the same way as adults. A 'nonstandard' pattern of inversion found in child speech (reported in Menyuk 1969 p. 73, Hurford 1975, and Kuczaj 1976) is that illustrated in (39) below: (39)(a) (b) (c) (d) (e) (f) (g) (h) Where does the wheel goes? What did you bought? What did you did? What did you got? What did you found? What did I told? What did she bought you? Did you came home? A related phenomenon is found in negative sentences – cf. the following data from Kuczaj 1976: (40)(a) (b) (c) (d) (e) You didn't had some She didn't goed The plant didn't cried I didn't saw that You didn't started it Such examples suggest that the tense/agreement inflections on the dummy auxiliary do are somehow copied on the main verb. But why? There are two observations which may provide us with a clue to what is going on here. One is that auxiliariless positive declarative sentences are derived (within Pollock's framework) by moving an abstract 'dummy' auxiliary (a null counterpart of do) from AGR into T, whence the inflections carried by the dummy auxiliary in T are lowered onto V: we might conjecture that the relevant children extend this pattern to the overt dummy auxiliary do (while simultaneously realizing the inflections on do as well). A second relevant factor may be that (in Pollock's analysis) dummy do is thematically chained with the main verb, in that do inherits the thematic properties of the main verb: it may be that this thematic relation is formally signalled via a form of agreement which involves realizing the tense/agreement affixes on both links of the relevant theta-chain, hence both on do and on the verb with which it is thematically chained. A second 'nonstandard' pattern of inversion which has been reported in the relevant literature is that some children (sporadically or systematically) fail to invert (some or all) auxiliaries in contexts where inversion is obligatory in adult English, particularly in direct wh-questions. This phenomenon was first described in Ursula Bellugi's early work (Bellugi 1965, Klima and Bellugi 1966): she reported a stage of development at which children have inverted auxiliaries and dosupport in yes-no questions, but not in wh-questions. Among the data she used to support this claim were the following: (41)(a) (b) Will you help me? Where the other Joe will drive? (42)(a) (b) Can I have a piece of paper? What he can ride in? In Radford 1987, I proposed a structural account of this phenomenon, to the effect that the children concerned had misanalyzed wh-movement as a form of head-to-head movement under which a wh-head (e.g. a wh-pronoun like what) is moved into an empty C position. If we were to assume that inversion is also movement into an empty C, it would follow that children can only prepose either a wh-word, or an auxiliary – not both. If we further suppose that at the earliest stages of development, English-acquiring children operate with a positive setting for the whparameter (and so treat English as requiring obligatory syntactic wh-movement), then it follows that children will move auxiliaries from T into C in yes-no questions, but not in wh-questions (since the wh-word will obligatorily move into C, so blocking movement of the auxiliary from T into C). At first sight, it might seem implausible to suppose that wh-movement could involve movement of a wh-head into C. We might argue that this kind of movement is never found in adult grammars and hence would not be licensed by principles of UG. However, it is far from clear that movement of a wh-head would be illicit. In this respect, it is interesting to note the following data from Northern Norwegian given in Taraldsen 1986, p. 21: (43)(a) Kor i byen ska [studentan bu]? Where in town will students stay? 'Where in town will the students stay?' (b) *Kor i byen [studentan ska bu]? Where in town students will stay (idem) (44)(a) Kor [studentan ska bu] ? Where students will stay 'Where will the students stay?' (b) *Kor ska [studentan bu]? Where will students stay (idem) One way of analyzing such data is as follows. We might suppose that when a wh-phrase such as [kor i byen] is fronted, it cannot move into C, since this is a head position, not a phrase position: hence, it must move into the phrasal specifier position in front of C. This leaves C empty, so that C can then be filled by a preposed V such as ska, as in (43) above. But we might also suppose that wh movement may also move a wh-head, and that when it does – as in (44) – it moves the wh-head not into the specifier position within CP (since this is a phrasal position), but rather into the head C position. This means that C is then filled by the preposed wh-head, so that C can no longer serve as the landing-site for a preposed Verb like ska - hence the ungrammaticality of (44)(b). Of course, this analysis crucially presupposes that preposed wh-words in Northern Norwegian are moved into C. Thus, any claim that C is not a licit landing-site for a preposed whhead in any natural language grammar would be falsified by the Norwegian data described above (assuming the analysis presented here). If we extend this kind of analysis of wh-movement (as movement of a pronominal wh-head into C) to the child data in (41-2) above, we should expect to find that the relevant children invert auxiliaries in yes-no questions, but not in wh-questions (as Bellugi claims). However, the observational basis of this claim would seem to be called into question by the fact that the Bellugi data do show examples of wh-questions with both a wh-word and an auxiliary fronted - cf. e.g. the following: (45) What did you doed? One interpretation of data like (41-2) and (45) is that they show that auxiliaries sporadically invert in wh-questions. If this is so, then the wh-head-movement analysis cannot be right, so we need to find an alternative account of the data. It seems natural to suppose that 'inverted' wh-structures like (45) are CPs in which the auxiliary is in the head C position and the wh-expression in the specifier of CP. Thus, our problem is to account for uninverted wh-structures like (41-2). An alternative answer which we might explore (cf. Radford 1990a, p. 135) is to suppose that wh-movement in structures such as (41-2) involves adjunction to TP, in much the same way as topicalization involves adjunction to TP in adult English structures such as: (46) You must realize that [TP this kind of behaviour [TP I will simply not tolerate]] Rudin (1988) provides data which can be interpreted as showing that wh-movement may involve adjunction to TP in Polish, in structures such as: (47) Maria mysli, ze [TP co [TP Janek kupil-]] Maria thinks that what Janek bought? 'What does Maria think that Janek bought?' We might then suppose that a phrase adjoined to TP will block movement of a head from T to C: this assumption seems motivated by the ungrammaticality of structures such as: (48) *[CP [C Will] [TP this kind of behaviour] [TP you tolerate]]]? Accordingly, we might posit that wh-movement may be analyzed by the child as either a substitution operation (movement into the specifier of CP) or an adjunction operation (adjunction to TP), and that it will then follow from independent principles of UG that inversion will be licensed when wh-movement involves substitution within CP, not adjunction to TP. One final 'nonstandard' pattern of inversion which I shall comment on here is illustrated by the following examples (produced by Knox at age 42 months): (49)(a) (b) (c) What are you doing? Where is Wa-wa sitting? What are they doing? What are they going to do? What have they done? Where does she go? Where you can put them? Where you can go? What you would like? Why him need be a doctor? Shall we go outside? Can't you tell? Such data suggest that only auxiliaries inflected for agreement (like have and be) are preposed in wh-questions, not agreementless modals (although modals are preposed in yes-no questions). Why should this be? We might explore an answer to this question is terms of licensing. Fukui (1986: 52-4) argues that the specifier position for functional categories can only be filled when the head functional category carries an appropriate set of functional features to license the occurrence of the specifier. For example, a nominative pronoun is only licensed to appear in the specifier position of TP when the head T is finite. We might similarly suppose that in adult English, a wh-phrase is only licensed to appear in the specifier position of CP in a root clause when the head C carries tense properties (i.e. in effect when C contains an auxiliary preposed from T into C). One way in which we might seek to analyse data such as (49) is to suppose that in Knox's grammar, a preposed wh-phrase is licensed by an AGR constituent (i.e. a wh-phrase can occupy the specifier position of CP when licensed by an agreement-marked auxiliary occupying the head C position of CP), but not by a T constituent (hence an agreementless modal T constituent in C does not license a wh-specifier). What makes it all the more plausible to posit that a wh-specifier might be licensed (in some child grammars) by an AGR in C is the fact that we find sporadic examples which might be analysed as involving agreement of a preposed auxiliary with its CP specifier (rather than with its putative 'true' subject in the specifier of TP): cf. (50)(a) (b) (c) (d) What's the wheels doing? (Holly 24) What's those? (Alistair 30) What's you doing? (Ellen 33) What's they doing? What's they called now? (James 34) (51)(a) (b) (c) (d) Where is his feet? (Jonathan 39) Where's me? (Michelle 29 = 'Where am I?') Where's we going tonight? (James 34) Where is you? (Elspeth 39 = 'Where are you?') If we suppose that what and where are third person singular pronouns positioned in the specifier position of CP, and that the preposed Auxiliary be occupies the head C position of CP, then such examples would seem to suggest that a wh-specifier may agree with the item occupying the head C position of CP – so making it more plausible to posit that AGR in C may license the occurrence of a preposed wh-phrase in the specifier position of CP. The specifier-head mislicensing approach might be extended to handle the phenomenon reported in Slobin (1979: 79), whereby some children invert positive auxiliaries but not negative auxiliaries in wh-questions. Slobin provides the following dialogue to illustrate this phenomenon: (52) ADULT: Adam, ask the old lady where she can find some toys ADAM: Where can you find some toys? ADULT: Adam, ask the old lady why she can't run ADAM: Old lady, why you can't run? One approach to this problem might be to suppose that positive auxiliaries license wh-specifiers, but negative auxiliaries do not. Another might be to suppose that (in order to reflect the scope relations) NEG originates above the modal in T in such cases, and that T adjoins to NEG to form a compound NEG constituent can't which (being a NEG constituent rather than a T constituent) cannot then raise to C. The specifier licensing approach might be extended to account for the otherwise puzzling occurrence of inversion in declarative sentences such as those in (53) below: (53)(a) (b) In the water was it cold (Jonathan 27) That can't you play with (Andrew 32) Such data might suggest that the relevant children license a focussed constituent to appear in the specifier position of CP only if the head C position carries tense properties (i.e. if C is filled by an auxiliary which has moved out of T into C). What in essence we have suggested about sentences such as (49-53) is that they all involve (what from an adult perspective might be classed as) specifier-head mislicensing: i.e. the children concerned fail to correctly identify the range of functional heads which license a specific type of specifier, or the range of specifiers which are licensed by a given functional head. This pattern of mislicensing is by no means restricted to the C system: for example, it is also found in the T system, in that many children license not just a nominative expression in the specifier position of TP, but also an objective and/or genitive specifier. One child in my corpus alternated between all three forms for finite subjects: cf. (54) My did get my leg dry. I got my leg dry. My want sauce, Mummy. I want sauce on this dinner. Me watch you. Me make bubbles. Me'll have that (Betty 30) (See Radford 1991a for a discussion case-marking in child English, and Radford 1991b for a discussion of the phenomenon of specifier-head mislicensing.) 7. Summary This paper has set out to investigate the structure of the verbal clauses produced by young children between one and three years of age acquiring British English as their first language: the theoretical framework used is the 'articulated functional categories' framework of Pollock 1989, outlined in section 1. In section 2, we argued that the earliest verbal clauses produced by oneyear-old children are lexical-thematic VPs like (2), in which every non-maximal projection is a theta-assigner, and every maximal projection is assigned a theta-role by any sister constituent which it has. It follows that children have no T system at this stage (hence no productive use of modals, or the past tense +d inflection), no AGR system (hence no dummy do auxiliary and no third person singular +s inflection), and no C system (hence no complementisers and no inverted auxiliaries). In section 3, we considered possible explanations for the absence of functors in early child grammars, concluding that the functional parametrization hypothesis and the maturational hypothesis seemed to provide the most promising account. However, we noted that neither hypothesis directly predicted the order of acquisition of functors, and that this would have to be determined by external factors (e.g. the relative complexity of different functors). Given that we could find no evidence for claiming that any one of the three relevant functors (C, T and AGR) is intrinsically substantially more complex than any other in English, we were led to expect that all three might be acquired at roughly the same stage of development. We went on to claim that there is evidence from two different studies (Aldridge 1989 and Radford 1990a) that the three are acquired in parallel, and that by around the age of two years, most children have developed a rudimentary T system, AGR system and C system. In the remainder of the paper, we went on to consider ways in which the C/T/AGR systems developed by two- and three-year olds sometimes diverge from the corresponding adult systems. In section 5, we noted that most children miscategorize perfective have as a base-generated AGR constituent (so that have has no non-finite forms), but that some children seem to miscategorize perfective have (and dummy do as well) as a base-generated T constituent (lacking agreement inflections): we also noted sporadic examples of be miscategorized as a nonauxiliary verb, and of go miscategorized as an auxiliary. In section 6, we noted that T and AGR constituents in child speech often have null allomorphs, so that some modal T constituents and the dummy AGR auxiliary do may be null, and likewise T and AGR inflections may also be null. In section 7, we defended the view that auxiliary inversion in child speech is movement from T to C; we noted that this would provide a natural account of why some children miscategorize preposed auxiliaries as complementisers. We went on to look at how inversion in child speech may differ from its adult counterpart. We noted that for some children, tense/agreement inflections in structures involving do-support may surface both on do and on the main verb, and we conjectured that this might be a way of morphologically encoding the fact that dummy do inherits the thematic properties of the main verb. We discussed Bellugi's observation that some children fail to invert auxiliaries in wh-questions, and suggested that this was attributable to a misanalysis of wh-movement on the part of the relevant children (either as a wh-head-movement operation, or as adjunction of a wh-phrase to TP). Finally, we noted the curious case of a child who inverted agreement-marked auxiliaries, but not agreementless auxiliaries, conjecturing that this type of error might be part of a more general mislicensing phenomenon, whereby children have not yet determined (correctly, at least) the range of specifiers licensed by a given type of functional head, or the range of functional heads which license a given type of specifier. The overall conclusion to be drawn from our discussion is thus that there are really only two major stages in the acquisition of verbal clauses in child English – an earlier lexical stage, and a later functional stage. When children reach the functional stage (typically at around two years of age) all three functional superprojections of the verb (AGRP, TP and CP) seem to come on line together. The essential thrust of our argumentation has been that once these functional category systems are 'in place', they stay 'in place' (albeit sometimes in an abstract form), so that the verbal clauses produced by two- and three-years olds who have already reached the functional stage of development are invariably complex CP/TP/AGP/VP structures. Apparent deviations from the adult norm in two- and three-year old children thus do not represent a 'simplified' clause structure lacking certain functional projections, but rather a misanalysis of certain properties of specific functional systems. 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