CAS LX 522A1
Topics in Linguistics:
Language Acquisition
Week 1b. Principles, parameters,
triggers, and subsets
Principles and Parameters
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The proposed solution to the apparent
paradox is to suppose that to a large extent
all human languages are the same. The
grammatical systems obey the same
principles in all human languages.
English
UG
Japanese
Principles and Parameters
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Languages differ, but only in highly limited ways.
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In the order between the verb and the object.
In whether the verb raises to tense
…
English
UG
Japanese
Principles and Parameters

This reduces the task for the child immensely—all
that the kid needs to do is to determine from the
input which setting each of the parameters needs
to have for the language in his/her environment.
English
UG
Japanese
The standard picture
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The way this is usually drawn schematically is
like this. The Primary Linguistic Data (PLD)
serves as input to a Language Acquisition
Device (LAD), which makes use of this
information to produce a grammar of the
language being learned.
PLD
LAD
grammar
The standard picture
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This isolates the innately specified language
faculty into a single component in the picture.
The LAD contains (a specification for) all of
the principles and the parameters, and has a
procedure for going from PLD to parameter
settings.
PLD
LAD
grammar
Modeling human language
capacity
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We may be able to avoid confusion later,
though, if we differentiate the innately
provided system into its conceptual
components.
This is my rendition of a way to think about
UG, parameters, and LAD.
LAD
UG
PLD
Binding Theory
Subjacency
Modeling human language
capacity
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UG provides the parameters and contains the
grammatical system (including the principles,
like Subjacency, Binding Theory, etc.) that
makes use of them.
LAD sets the parameters based on the PLD.
Responsible for getting language to kids.
LAD
UG
PLD
Binding Theory
Subjacency
Modeling human language
capacity

The idea behind this diagram is that UG is
something like the shape of language knowledge.
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Knowledge of language can only take a certain,
innately pre-specified “shape”.
A system with this “shape” has certain properties,
among them Binding Theory, Subjacency, … the
Principles.
LAD
UG
PLD
Binding Theory
Subjacency
Modeling human language
capacity

The Parameters are different ways in which
stored knowledge can conform to the “shape”
of UG.
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The LAD is a system which analyzes the PLD
and sets the parameters.
LAD
UG
PLD
Binding Theory
Subjacency
Principles and Parameters

So two languages which differ with respect to
one parameter setting might be represented
kind of like this.

This is of course a cartoon view of things, but
perhaps it might be useful later.
Language
A
Language
B
Principles and Parameters
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So what are the Principles and Parameters?
Good question! —and that’s what theoretical
linguistics is all about.
Since 1981, many principles and parameters have
been proposed. As our understanding of language
grows, new evidence comes to light, and previous
proposals are discarded in favor of better
motivated ones. It’s hard to keep a current tally of
“the principles we know of” because of the active
nature of the field.
Principles and Parameters
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Some of the (proposed) Parameters that have
received a fair amount of press are:
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Bounding nodes for Subjacency
Binding domain for anaphors and pronouns
Verb-object order
Overt verb movement (V moves to tense)
Allowability of null subject (pro) in tensed clauses
We’ll look at each of them in due course…
Verb-object order
The parameter for verb-object order (more
generally, the “head parameter” setting out the
order between X-theoretic head and
complement) comes out as:
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Japanese: Head-final (X follows complement)
English: Head-initial (X precedes complement).
Figuring out which type the target language is is
often fairly straightforward. Kids can hear
evidence for this quite easily. (Not trivial, though—
consider German SOV-V2)
Principle A
22) Sam believes [that Harry overestimates himself]
23) Sam-wa [Harry-ga zibun-o tunet-ta to] it-ta]
Sam-top Harry-nom self-acc pinch-past-that say-past
‘Sam said that Harry pinched him(self).’
Principle A
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Principle A. A reflexive pronoun must
have a higher antecedent in its binding
domain.
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Parameter: Binding Domain
Option (a): domain = smallest clause
containing the reflexive pronoun
 Option (b): domain = utterance containing the
reflexive pronoun
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But how can you set this
parameter?
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Every sentence a kid learning English hears is
consistent with both values of the parameter!
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If a kid learning English decided to opt for the
“utterance” version of the domain parameter,
nothing would ever tell the kid s/he had made a
mistake.
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S/he would end up with non-English intuitions.
But how can you set this
parameter?
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A kid learning Japanese can tell right away
that their domain is the sentence, since
they’ll hear sentences where zibun refers
to an antecedent outside the clause.
But how can you set this
parameter?
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The set of sentences allowed in English is a
subset of the set of sentences allowed in
Japanese. If you started assuming the English
value, you could learn the Japanese value, but
not vice-versa.
Sentences allowed in Japanese (domain = utterance)
Sentences allowed in English (domain = clause)
Subset principle/defaults
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Leads to: The acquisition device selects
the most restrictive parametric value
consistent with experience. (Subset
principle)

That is, for the Principle A domain
parameter, you (a LAD) start assuming
you’re learning English and switch to
Japanese only if presented with evidence.
What it takes to set a
parameter
J
E

Binding domain parameter
Option (a): Binding domain is clause.
 Option (b): Binding domain is utterance.
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English = option a, Japanese = option b.
What it takes to set a
parameter

Binding domain parameter
Kids should start under the
assumption that the
parameter has the English
setting.
 If they hear only English
sentences, they will stick with
that setting.
 If they hear Japanese
sentences, they will have
evidence to move to the
Japanese setting.
J
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E
What it takes to set a
parameter
Very sensible. Now, let’s
consider another parameter of
variation across languages.
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I
E
Null subject parameter
Option (a): Null subjects are permitted.
 Option (b): Null subjects are not permitted.
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Italian = option a, English = option b.
What it takes to set a
parameter
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The Subset principle says that
kids should start with the English
setting and learn Italian if the
evidence appears.
But even English kids are wellknown to drop subjects early on in
acquisition. As if had the Italian
setting for this parameter.
I
E
Moreover…
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English kids hear looks good and seems ok and
stop that right now. Why don’t they end up
speaking Italian? If they mis-set the parameter,
how could they ever recover?
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Italian kids hear subjectless sentences—why
don’t they interpret them as imperatives or
fragments (so as not to have to change the
parameter from the default)?
Triggers
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It seems like actual occurrence of null
subjects isn’t a very good clue as to
whether a subject is a null subject
language or not.

Are there better clues? If a strapping
young LAD were trying to set the null
subject parameter, what should it look
for?
Triggers

Turns out: Only true subject-drop languages
allow null subjects in tensed embedded clauses.
24) *John knows that [— must go].
(English)
25) Juan sabe que [— debe ir].
(Spanish)
‘Juan knows that [he] must go.’
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Perhaps the LAD “knows” this and looks for
exactly this evidence. Null subjects in embedded
tensed clauses would be a trigger for the
(positive setting of the) null subject parameter.
Triggers
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A potential problem with the proposed
subject-drop trigger is that it requires complex
sentences—you need to look at an
embedded sentence to check for the trigger.
Such sentences might be too complicated for
kids to process.

Degree-1 learnability: Triggers need look no
lower than 1 level of embedding.
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Degree-0 learnability: Triggers need look
only at main clauses.
Triggers
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Many who work on learnability have
adopted the hypothesis that triggers
need to be degree-0 learnable.
Subjacency. *[wh … [a … [b … t … ] ]
where a and b are bounding nodes.
IP and TP
are often
used interchangeably
Bounding node parameter for IP:
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Option (a): IP is a bounding node (English).
Option (b): IP is not a bounding node (French, Italian).
Triggers
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Thus, a kid learning French couldn’t choose
option (b) by hearing this…
28) Violà un liste de gens… ‘there is a list of people…’
[à qui on n’a pas encore trouvé [quoi envoyer t t ]]
to whom one has not yet found [what to send]]

…since that’s a degree-2 trigger. But…
Triggers
29) Combien as- [IP tu vu [DP t de personnes]]?
How-many have you seen of people
‘How many people did you see?’
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If IP were a bounding node, this should be
ungrammatical in French, so this can serve
as (degree-0) evidence for option (b).
Triggers
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Principles are part of UG
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Parameters are defined by UG
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Triggers for parameter settings are defined
as part of the LAD.
Navigating grammar spaces
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Regardless of the technical details, the
idea is that in the space of possible
grammars, there is a restricted set that
correspond to possible human grammars.

Kids must in some sense navigate that
space until they reach the grammar that
they’re hearing in the input data.
Learnability
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So how do they do it?
Where do they start?
What kind of evidence do they need?
How much evidence do they need?
Research on learnability in language
acquisition has concentrated on these
issues.
Are we there yet?
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There are a lot of grammars to choose from,
even if UG limits them to some finite number.
Kids have to try out many different grammars to
see how well they fit what they’re hearing.
We don’t want to require that kids remember
everything they’ve ever heard, and sit there and
test their current grammar against the whole
corpus of utterances—that’ a lot to remember.
Are we there yet?

We also want the kid, when they get to the
right grammar, to stay there.
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Error-driven learning
Most theories of learnability rely on a kind of
error-detection.
 The kid hears something, it’s not generable by
their grammar, so they have to switch their
hypothesis, to move to a new grammar.
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Plasticity
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Yet, particularly as the navigation progresses,
we want them to be zeroing in on the right
grammar.
Finding an error doesn’t mean that you (as a kid)
should jump to some random other grammar in
the space.
Generally, you want to move to a nearby
grammar that improves your ability to generate
the utterance you heard—move in baby steps.
Triggers
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Gibson & Wexler (1994) looked at learning
word order in terms of three parameters
(head, spec, V2).
Their triggering learning algorithm says if
you hear something you can’t produce, try
switching one parameter and see if it
helps. If so, that’s your new grammar.
Otherwise, stick with the old grammar and
hope you’ll get a better example.
Local maxima
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A problem they encountered is that there are
certain places in the grammar space where you
end up more than one switch away from a
grammar that will produce what you hear.
This is locally as good as it gets—nothing next to
it in the grammar space is better—yet if you
consider the whole grammar space, there is a
better fit somewhere else, you just can’t get
there with baby steps.
Local maxima

This is a point where any move you make is
worse, so a conservative algorithm will never get
you to the best place. Something a working
learning algorithm needs to avoid. (And kids,
after all, make it).
MLU

Kids’ linguistic development is often
measured in terms of Mean Length of
Utterance (MLU).
Can be measured in various ways (words,
morphemes)
 Gives an idea of kids’ normal utterance length
 Seems to correlate reasonably well with other
qualitative changes in kid productions
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2-year olds
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Around 2 years old
Around MLU 1.75
Around 400 words in the vocabulary
1-3 word utterances
Word order generally right
Grammatical words (the, is) generally
missing
2 1/2 year olds
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About 2 1/2 to 3 years
About MLU 2.25
About 900 words in the vocabulary
Some grammatical devices (past tense -ed,
verbal -ing).
Over-regularization errors (He goed in the
house), indicating they’ve grasped the rule of
past tense formation.
Single clause sentences
3 and 4 year olds
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About 3 to 3 1/2 years, MLU about 2.75,
about 1200 words, beginning to use
syntactic transformations (Is Daddy mad?
Where is he going?)
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About 3 1/2 to 4 years, MLU about 3.5,
about 1500 words, multi-clause sentences,
still some over-regularization
4 and 5 year olds
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4-5 years, MLU around 4, about 1900
words, using more conjunctions and
temporal terms (before, after), gain some
metalinguistic awareness.
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After 5, MLU stays about the same (no
longer predictive), sentences get more
complex, vocabulary increases (more
slowly), over-regularization decreases…
How do we describe multiword utterances?

Syntactically, in the same terms as the
adult grammar? (continuity)

Or discontinuously? (For some reason,
people seem to think this is simpler…)
Thematic (agent+action, action+theme, …)
 Pivot (P1 + O, O + P2, O + O, O)
 “Limited scope formulas” (here+X, want+X)

Syntactic approach

Continuity: 
VP

V
sit
VP
PP
V
PP
sit
P
on
NP
chair
P
NP
chair
Why 2 words?

Maybe they omit words they don’t
know?

Well, but they do omit words they know.
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A kid who’s used hurt before, documented as
saying baby cheek to mean ‘baby hurt cheek.’
Pinker (1984): Processing bottleneck
A 2-word utterance “filter”
 Kids “grow out” of this constraint.
 Still, kind of mysterious. What’s easier?
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So, do kids have syntactic
categories?
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There’s not really any clear way to know at
the earliest (one word) stages.
One view is that the null hypothesis (which
we adopt, lacking evidence to the contrary)
should be that kids do have adult-like
syntactic categories.
Continuity. Kids end up being adults with
adult syntactic categories; if they initially
categorize words differently, we need to
explain how they change their categorization
to the adult type.
Do kids at the one-word stage
have/know syntactic
structure?
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Early attempt to answer the question.
Based on comprehension—kids clearly
understand more than they can produce.
de Villiers & de Villiers (1973), kids around
MLU (mean length of utterance) 1 to 1.5
asked to act out the truck pushes the car,
and got it right only about a third of the
time.
Do kids at the one-word stage
have/know syntactic
structure?

Hirsh-Pasek & Golinkoff (1991),
preferential looking task. Less
burdensome task. Significant preference
for correct screen (word order & role).


Hey,Cookie
Monster is
tickling Big
Bird.
Evidence for structure
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Recall also the Hirsh-Pasek & Golinkoff
(1991), preferential looking task.
Structure plays a crucial role in figuring out
which screen to look at.


Hey,she’s
kissing the
keys.
One-substitution

Anecdotal evidence:
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Hamburger & Crain (1984): ‘Point to the first
green ball. Ok. Now, point to the second one.’
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nice [yellow pen], nice one (1;11)
Note: “Failure” wouldn’t tell us anything here,
since one could also legitimately mean ball—but if
kids take one to mean green ball, that’s evidence
that kids do have the syntactic sophistication to
replace N with one.
Nevertheless, 42 / 50 kids interpreted it as
green ball.
Some properties of kidspeak

Kids’ language differs from adult language
in somewhat predictable ways. These can
serve as clues to kids’ grammatical
knowledge. Up to around 3 or so…
Case errors for nouns
 Some word order errors
 Omitted subjects
 Verbs not (always) fully inflected

Word order errors?
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Languages vary with respect to word order
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SVO
VSO
SOV
SOV+V2
English, French, Mandarin, …
Tagalog, Irish, …
Japanese, Korean, Turkish, …
German, …
Clahsen (1986) reports that German kids don’t
manage to put the verb in second position until
the finite/nonfinite distinction is “mastered.”
But at that point the change was immediate:
Sentence-syntactic properties are stored
separately from word’s category properties.
Word order errors?
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Surprisingly few—95% correct in English, DPinternal order (*black the dog) may be at 100%.
Yet there are a number of things like: Doggy sew.
It appears that in these cases, it is theme+V
without an expressed agent. When agent is
expressed, themes are in their place.
Sounds like an unaccusative or a passive—
perhaps they are treating the verb in these cases
as unaccusatives? An attractive idea—but for the
fact that young kids are bad at passives and
unaccusatives.
Word order errors

Occasionally, postverbal subjects occur—but
these seem to occur with likely unaccusatives
with postverbal subjects on occasion: going it,
come car, fall pants. (cf. adult Mandarin , or
Italian, which would allow that).

Alternative approach to Doggy sew might be
topicalization: Doggy, you sew—if kids actually
can’t do passives and unaccusatives, then this
might be the only explanation (short of pure
performance error).
The Bennish optative
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Anecdote about Ben, from Sadock (1982)
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Intransitives (subject follows verb)
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SVO normally, but in optative (wish) constructions, he
uses a weird word order.
Fall down Daddy. ‘Daddy should fall down’
Eat Benny now. ‘Let Benny eat now.’
Sit down Maggie, Mommy.
‘Maggie should sit down, Mommy.’
Transitives (subject marked with for)
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Pick up Benny for Daddy.
‘Daddy should pick Ben up.’
Read a story for Mommy.
‘Mommy should read a story.’
The Bennish optative
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He’s marking transitive subjects with for, but
leaving intransitive subjects and objects
unmarked.
In the optative, Ben treats transitive subjects
differently, and objects and intransitive subjects
the same way.
This pattern is reflected in a type of adult
language as well. Ergative languages mark
subjects of transitives differently from both
objects and intransitive subjects.
Accusative languages (like English) mark
objects differently (I left, I bought cheese, Bill
saw me).
The Bennish optative
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Perhaps Ben’s language is ergative in the
optative mood. (An option for adult
languages, though clearly not in his
parents’ language)
Further evidence:
Ergative case marker is often homophonous
with marker for possessive (cf. Inuktitut -up
used for both), and Ben uses for (his ERG
marker) in possessive constructions as well.
 That’s a nose for Maggie ‘That’s Maggie’s
nose.’
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The Bennish optative
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Further evidence:
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Ergative languages are almost invariably split often
along semantic lines. Sadock takes the optative
restriction to be of this type (cf. Georgian, nominativeaccusative most of the time, except in the subjunctive
and aorist, where it is ergative-absolutive)
Ben’s not really making word order errors,
exactly—he just thinks he’s speaking Georgian.
His errors come from among the options.
Pre-subject negation
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Kids will say things like:
No I see truck
 Not Fraser read it
 No lamb have a chair either.
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Anaphoric no? ‘No, I see the truck.’
Often distinguishable from context, and
they are not all anaphoric.
Pre-subject negation
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Déprez & Pierce 1993 looked at these,
and proposed that not Fraser read it
comes from a failure to raise the subject
out of SpecVP to SpecIP. That is, here,
Fraser is still in its VP-internal subject
position.
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Some believe this, some don’t, but it’s a
well-known analysis.
Case errors
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English pronouns exhibit Case
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Kids seem to make errors until at least 2.
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Nom: I, he, she, they
Acc: me, him, her, them
Gen: my, his, her, their
me got bean
her do that
me eye
In general, it is often overgeneralization of Acc.
Overuse of accusative
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Default case: Acc in adult English (Schütze
1997)
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Me too.
What, me cheat?! Never!
Me, I like pizza.
It’s me.
—Who did this? —Me.
So, “overuse of accusative” may well be just
using a default form for nouns which don’t have
case.
Default Case
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Russian (Babyonyshev 1993): Default
case appears to be Nom.
Russian kids make basically no errors in
subject case.
…but they overuse Nom in other positions
(e.g., Nom instead of Acc on an object).
Default Case
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German (Schütze 1995): Default case also
appears to be Nom:
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Was? Ich dich betrügen? Nie!
‘What? I cheat on you? Never!’
Der, den habe ich gesehen.
‘He, him I saw.’
Object case errors are more common than
subject case errors, and usually involve
overgeneralization of Nom.
Determiners
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Kids will also often leave out determiners.
Hayley draw boat.
 Turn page.
 Reading book.
 Want duck.
 Wayne in garden
 Daddy want golf ball.
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Subject drop
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Even in languages which don’t allow null
subjects, kids will often leave subjects out.
No turn.
 Ate meat.
 Touch milk.
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Dropping the subject is quite common—
dropping other things (e.g., object) is quite
rare.
Subject vs. object drop
Percentage of Missing subjects and
Objects from Obligatory Contexts
70
A
Subjects
Objects
60
50
E
S
Subject 57
61 43
Object
7
40
30
20
10
0
Adam
Eve
Sarah
8
15
Root infinitives
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Another, fairly
recently-noticed
aspect of kid speech
is that they will use
infinitive verbs
sometimes when
adults would use finite
verbs. In lots of
languages.
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French:
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German:
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Pas manger la poupée
not eat[inf] the doll
Michel dormir
Michel sleep[inf]
Zahne putzen
teeth brush[inf]
Thorstn das haben
Thorsten that have[inf].
Dutch:
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Ik ook lezen
I also read[inf.]
Root infinitives
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English kids do this too, it turns out, but
this wasn’t noticed for a long time.
It only write on the pad (Eve 2;0)
 He bite me (Sarah 2;9)
 Horse go (Adam 2;3)
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It looks like what’s happening is kids are
leaving off the -s.
Taking the crosslinguistic facts into
account, we now think those are nonfinite
forms (i.e. to write, to bite, to go).
Root infinitives
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However, children learning some
languages seem to show very few root
infinitives or none at all.
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Italian, for example.
Often these languages with very few root
infinitives
Allow null subjects
 Have fairly complex agreement morphology
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Pulling it all together
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Kids sometimes use nonfinite verbs.
Kids sometimes leave out the subject.
Kids sometimes use the wrong Case on
the subject (looks like a default Case).
Kids sometimes get the word order wrong
(specifically, with respect to negation and
for V2).
Kids generally leave out determiners.
Kid grammars

A major research industry arose trying to
explain how these properties of child
speech come about (and how they relate
to each other) in terms of the grammatical
and/or performance abilities of children.
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