Language Acquisition and Language Disruption
Tutorial 3: Lexical Development and Syntactic Development.
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Last week:
Theories: We saw that the Acquisition of language involved Imitation, reinforcement, child
directed speech, analogy but that was more to it, we proposed that there is an underlying
rules system which adds the acquisition of language.
Acquisition of sounds: of language the phonemes. How these phonemes are concatenated to
form syllables and morphemes and words. Compare the three of these
sounds:
[ b, g, k, t, d, s, e, i]
syllable:
unit of pronunciation
morphemes: smallest part of a word with meaning
bandage -> 1m, 2s
kicked -> kick_ed 2m, 1s
stuttered -> stutter_ed 2m and 2s
This week:
 Lexical development
 Syntactic development
Lexical development:
Spoken and sign language happen at the same time.
Common nouns are generally the first words, verbs, adjectives and function words are rare
(especially compared to their proportions in maternal use).
Expressions of displeasure or rejection (no) and social interaction (please, bye). By the age
of 6, most children have a vocabulary of 13 000 words.
The acquisition of word meaning involves the process of mapping concepts onto sounds or
signs. But children do not learn the meaning of words just by connecting a name with an
object that they see or is pointed to them and the word uttered at the same time. (how
would blind children learn the meaning of words?). Also, adult speech directed at children
often involves past and future and objects not in sight.
The sort of words that children have to learn and the circumstances under which they are
learnt suggests that word learning cannot happen solely by raw observation of the cooccurring world.
Fast mapping: (Carey, 1978) Children grasp aspects of the meaning of words with very
little exposure. A word heard once before can be recalled over a month later. The meanings
for these early words also seem to be the same as for adult speakers, which then suggests
that word learning is supported by a pre-existing conceptual repertoire (a rich
understanding of objects, actions etc.).
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This suggests that word learning is supported by a pre-existing conceptual repertoire.
But even if they have the conceptual structure for word meaning acquisition, how can they
attach the correct word with the correct meaning? I.e. a new word in a new situation does
not necessarily mean that that is the word for that new situation or object. It has been
noticed that children regularly inspect the situation where that new word appears. So
children use pragmatic cues to figure word meaning too (i.e. follow the look of the speaker..)
Properties and strategies of learning the meanings of words:
The acquisition of ‘team’. Child is in school, the teacher tells them they will play a game of
football/basketball. the teacher divides the group into two teams and tells them to sit on a
mat with their team. Later the child is watching television and it’s sibling sits on it’s mat, it
says ‘he won’t stay away from my team’. It defined team as ‘group of people on a blanket’
Trial and error process.
Acquisition of word meaning is made systematic in two ways.
1. Children’s definitions have structure, they do not deviate randomly.
2. The order in which they are learned is reflected in the complexity of the item.
Definitions for words fall into 3 categories:
COMPLEXIVE CONCEPT: Basic semantic groups like chair, deck chair, patio, inflatable,
rocking easy, picks out class of nouns, things that can be sat on. nouns are used to single
out objects with something in common, chair- different types all can be sat on. Children fail
to define words like this, they must learn this. The meaning varies from one situation to
the next and so fails to pick out a class of objects. This is called a Complexive concept.
doggie understood to mean furry thing, like slippers, or something that moves by itself,
birds, toy cars. This is the most primitive conception of word meaning it creates a loose
bond between words that have similar properties but not class of objects.
OVEREXTENSION: range extended beyond adults.
fly -> dirt, dust, small insects, bread crumbs.
moon ->cakes, round marks, postmarks, the letter O.
ticktock -> clocks, watches, parking meters, dial on scales.
Compare with Compleive concepts.
They look as random as complexive concepts but they do not vary as the other does. <fly>
anything small, possibly mobile. <Moon> is applied to all round things, <ticktock> to something
with dial and figures.
This involves perceptual features: shape, size, colour taste. Adults do this too. Only sweet
things can be sweet, tomatoes have features of fruit but not considered so. But if like adult
why the overextensions? Child has only and incomplete definition: doggie as anything furry,
adults have property that doggie must have four legs, when this is acquired the field
narrows
UNDEREXTENSION: application of a words to a smaller set of objects than an adult. call
a ball ‘ball’ only when it’s under the couch. must learn that location is not a factor. Older
children: mammal ->dog, fruit -> apple. But whale and olive are in these categories but not
obviously so but the ‘ordinary’ members of the category.
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Why three classes of definition?
first one only present for shorter period. Over ext. used with limited vocabulary,
underextension is a more conservative use of language, perceiving limits where there are not
there. But over and under extending definintions the child may systematically get the
correct meaning.
Syntactic Bootstrapping: As children learn the meaning of words they are also learning the
syntax of the language. Syntax is said (Gleitman) to help children to acquire meaning.
‘blicking’ will be interpreted as a verb and blick a noun.
‘Some blick’ would be interpreted to be a substance like water,
‘John blicks Mary’ would be similar to hit,
‘John and Mary blick’ would have meaning like stand.
So children use their knowledge of syntax to learn whether the word is a noun or a verb.
example 2:
If a two year old is told that a new doll is ‘a Dax’, they will apply it to other similar looking
dolls whereas if the child is told that the doll is ‘Dax’ they will restrict the meaning to that
particular doll
Syntactic development:
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Children’s ability to construct grammar is not semantically based, but it can only be
explained by reference to syntactic categories and relations.
A child’s grammar deviates from adult grammar, but in highly specific constrained ways.
Even the deviant sentences produced by children are within the range of what could be a
human language. It seems that children just have not yet discovered which sentences are
and are not grammatical in the language they are acquiring. (In the same way, children
explore all possible sounds in their early stages of babbling). So children’s grammar does
follow the rules of universal principles.
Stages in syntactic development:
One-word stage (holophrastic stage): Starts between the age of 12 and 18 months.
Utterances are the length of one word, but often carry the meaning for a whole sentence,
like ‘up’ ‘ = I want up’, ‘more’ ‘ = I want more’.
Children seem to choose the most informative word that applies to the situation. Intonation
also plays a role in children’s utterances, it can be that of a question, statement or
imperative.
Two-word stage: Few months after one-word stage, between 18 and 24 months.
‘doggie bark’ The dog is barking, ‘hit doggie’ = I hit the dog. (understood perhaps through
observation)
Most of these two-word sentences have a correct word order and it is used consistently.
The order of the words conveys important part of the meaning in their utterances, i.e. only
word order is used to express the semantic relations:
Baby sleep
Kick ball
Sit chair
Mommy book
Block red
agent + action
action + object
action + locative
possessor + possession
entity + attribute
Most of the time children’s speech lacks function words and morphemes, like auxiliaries,
prepositions, articles and inflectional affixes.
Telegraphic stage: Longer and more complex utterances.
‘Chair broken’
‘Daddy like book’
‘What her name’
‘Me wanna show mommy’
But determiners and other non-lexical categories are still absent. The words and the word
order used still convey all the necessary information.
Later stages of development:
Morphemes and functional words start to appear in language in quite a consistent order.
First the verbal suffix –ing (she walking), then third person marker –s (she walks), then
past tense –ed (she walked) etc.
When the past tense –ed, is acquired, children overgeneralize it to concern all verbs, even
irregular ones, which they had ‘known’ before. (At the time when children used the correct
forms, they were just isolated forms that don’t fit into any pattern). The true irregular
verb forms are acquired relatively late.
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Negation and questions are also acquired in a consistent manner:
Negation:
First:
No baby sleep
Then:
Baby no sleep
Can’t, won’t and don’t are used and treated as just negative verbs, the forms can, will and do
are not acquired until later.
The verb be is also omitted from negative sentences as it is quite hard to use, hence
utterances like
I not break car
I not thirsty
Questions:
First with the use of intonation:
Mommy cup?
More ride?
At around 3 years of age:
Can and will and other auxiliary verbs in yes/no questions and with the correct word order:
Are you sad?
When using wh-questions, they fail with word order though:
Why you are sad?
The adult like sentences are produced when children learn to invert the subject and the
verb.
So all the mistakes that children make are not random, but reflect the system they are in
the process of constructing for themselves.
Assignment:
Do ONE of the following:
1. What is meant by the terms,
overextension and underextension?
What role do they play in language
acquisition?
2. What are the stages in the
acquisition of syntax?
One page, for Tuesday week
To be posted in pigeon hole outside
A208
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LEXICAL DEVELOPMENT
 FAST-MAPPING
 COMPLEXIVE CONCEPT
 OVEREXTENSION
 UNDEREXTENSION
 SYNTACTIC BOOTSTRAPPING
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STAGES IN SYNTACTIC
DEVELOPMENT:
 ONE-WORD STAGE
(HOLOPHRASTIC STAGE)
 TWO-WORD STAGE
 TELEGRAPHIC STAGE
 NEGATION
 QUESTIONS
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Stage development of a child
6-10 mnts:
1 yr:
18 mnts:
2 yrs:
2-3 yrs:
2-4 yrs:
4-5 yrs:
5+ yrs:
Babbling
Holographic period, one word phrases.
Two word stage, telegraphic stage.
Variation. stages.
Stage I: 400 wds, MLU 1.75. Adult wd
order. No used of articles, is, on.
Stage II: MLU 2.25, 900wds.
Pronouns, determiners, -ing, -ed used, also
Prepositions <in>, and <on>. Mono clausal
sentences, and overregularisation of past
tense and plural.
Stage III: MLU 2.75, 1200 wds.
Auxilary vbs, prepositions, grammatical
morphemes, and some syntactic
transformations.
Stage IV: MLU 3.5, 1500 wds.
Multi-clause sentences, relative clauses,
complement clauses. Overregularisations
still present.
Stage V: MLU 4.0, 1900 wds.
More conjunctions, subordinate clause,
temporal terms such as <before> and
<after>.
Stage VI: Vocab increases at slower rate.
Overregularisations gradually decrease,
forms are mastered.