Language and CognitionColombo, June 2011

Day 3Child Language and Disorders

Plan

• Questions of innateness• Modelling language processing in children• Acquisition of syntax

Why study language development?

• Acquisition of a complex cognitive system: understanding how children do this means we are understanding something substantial about how the human mind works

• Species-specificity: determining what it is that makes humans unique (if we are unique)

• Some children have difficulties acquiring language even in the absence of other apparent learning difficulties

• Cultural differences in language use can lead to difficulties in mainstream education

Issues in the study of language development

• Nature vs nurture: does the child acquire language from the environment, or is it genetically pre-programmed?

• Too simplistic: it’s certainly some combination of these two factors

• The debate now is more concerned with the “nature of nature”; what / how much is innately specified, and how much must be acquired

Is language innate?

Is language innate? Some arguments• no negative evidence• species-specificity• specified neurological and genetic

underpinnings• speed of language acquisition: around 2

years for most of the groundwork (cf. shoelace-tying)

• critical periods

No negative evidence

Father: where is that big piece of paper I gave you yesterday?

Abe: Remember? I writed on it.

Father: Oh, that’s right. Don’t you have any paper down there buddy?

Species-Specificity“. . . it is now widely recognized that these efforts have failed, a fact that will hardly surprise anyone who gives some thought to the matter. The language faculty confers enormous advantages on a species that possesses it. It is hardly likely that some species has this capacity but has never thought to use it until instructed by humans. That is about as likely asthe discovery that on some remote island there is a species of bird that is perfectly capable of flight but has never thought to fly until instructed by humans in this skill.” (Chomsky 1988).

Localization of function• Phrenology – Gall, Spurzheim, early 1800s

• Different cognitive functions can be localized to different parts of the brain

• Level of development of a particular function is reflected in skull formation

• The sad tale of Phineas Gage

• Dissociation of language from other cognitive faculties

Localization• Paul Broca (1861): patient ‘Tan’• Slow, effortful, nonfluent

speech with many omissions; but good comprehension

• on parle avec l’hemisphere gauche

• Carl Wernicke: patients with posterior lesions in the left hemisphere

• comprehension is impaired but speech is fluent

Genie: The Wild Child

Genie: The Wild Child

• Locked up in a room without language• Discovered at age 13 years• Could she recover language?• Is there a critical period for learning language?

Special cases

Johnson & Newport: Critical Period Effects for L2

Cerebral plasticity and language dominance

• Damage to language areas in young children may be associated with a shift in language function to the right hemisphere

• Plasticity is greater in younger brains – pathways are still being formed – “Equipotentiality” (Lenneberg 1967)

• But the LHS seems ‘specialized’ for language – there are usually some functional differences in cases of early childhood hemispheric shifts

• Language dominance appears to be established before birth– Planum temporale asymmetries are apparent as early as the third

trimester– Early hearing screenings show a right-ear advantage for linguistic

stimuli

Critical period

• Evidence from Wild Children• Evidence from L2 acquisition and attainment• Evidence from plasticity • Additional evidence: children who are not

exposed to sign language

Developmental sequences

What we study

• What’s the nature of the Language Acquisition Device?• How does it interact with environmental and social

influences to result in development of language?

An example: Stackhouse & Wells (1997)

Input• 'Physical sound wave' - a sound wave, whether speech or non-

speech, occurs in the environment.• 'Peripheral auditory processing' - the ear notices that a sound

has been heard.• 'Speech/non-speech discrimination' - the sound heard is

classified as being either speech or a non speech sound.• 'Phonological recognition' - speech sounds are classified as

being part of a known language. 'Like tuning a radio until you reach a channel where you recognise the language.‘

• 'Phonetic discrimination' - unusual speech sounds are processed here. This is used when speech sounds differ from the expected 'norm', for example, when processing different accents and dialects.

Representation

• 'Phonological representation' - whole words are stored according to how they sound

• 'Semantic representation' - the meanings of words are stored here

• 'Motor program' - the motor instructions required for speech muscles to produce the necessary sounds for words

Output

• 'Motor programming' - allows the production of words not previously known: copying a nonsense word such as 'short'; this enables the learning of new words.

• 'Motor planning' - allows for factors about how a word will be said, for example, quickly, loudly or with specific intonation.

• 'Motor execution' - the speech organs are activated and a word is articulated.

Questions

• How do children develop such a system?• How much of this framework do they bring to

the language acquisition situation? (i.e., how much is innate?)

• How much do they have to learn?• HOW do they learn this?

Principles and parameters

• Universal Grammar: The innately specified principles and properties that pertain to the grammars of all human languages

• Linguistic theory: A hypothesis about Universal Grammar

• Principles and Parameters: one such linguistic theory

Principles and parameters• Universal Grammar consists of – Principles: accounting for the similarities between

languages• E.g. Structure dependency, (extended) projection principle

– Parameters: accounting for variation between languages

Learnability• The Principles and Parameters hypothesis can

account for– the specific ways in which (the grammars of)

languages can differ and – the speed with which children acquire their

language• under this hypothesis, the child only has to choose

from among a narrowly restricted set of values in each of a limited number of innate parameters• constrains the hypothesis space• learning a language is reduced to parameter setting

and lexical learning

Acquisition of negation• Data from English, German & French• Stage 1 (about 24 months): Neg + sentence

No the dollie sleep.

Nein ich putt mache.No I kaputt make‘I didn’t break it.’

Pas la poupee dormir.Not the doll sleep.

Acquisition of negation• Stage 2 (about 28 months)• Constructions with negative marker but no

auxiliaries

The dollie no sleep.

Ich mache das nich. (adult negation)I do that not

La poupee dort pas. (adult negation)the doll sleep not

Acquisition of negation

• Stage 3 (about 36 months)• Negation with auxiliaries

I didn’t/can’t do it. (adult negation)

• Why does it take English children longer to acquire adult-like negation than it takes German or French children?

A negation parameter

• Either:– Any verb can carry negation, OR– Only auxiliary verbs can carry negation

• French, German: Any verb OK• English: only Aux OK• Aux is acquired late (Brown: 29-50 months)• So in languages where Aux is required to carry

negation, adult-like negation forms will also be acquired late

Question formation – adult grammar

Question formation – adult grammar

Question formation – adult grammar

Question formation – adult grammar

Question formation – adult grammar

Acquisition of questions

• Stage 1: sentence with external question markerMommy eggnog?Where milk go?

(Boy eat?)(What boy eat?)

Acquisition of questions

• Stage 2: Subject-Aux inversion in yes/no questions, but not in wh-questionsDoes the kitty stand up?Oh, did I caught it?Where the other Joe will drive?Why kitty can’t stand up?

(What the boy eat?)(What the boy did eat?)

Acquisition of questions

• Stage 3: subject-auxiliary inversion in wh questionsWhat did you doed?What does whiskey taste like?

(What did the boy eat?)

Back to the parameter• Only aux / any verb can carry negation• Reformulate: distinction between auxiliaries and lexical

verbs in terms of their distributional properties– English: yes– French, German: no

• In French or German, the lexical verb can be inverted to form a question– Dort la poupee? -- Schläft die Puppe?– *Sleeps the doll?

• In French or German, the lexical verb can carry negation– La poupee dort pas -- Die Puppe schläft nicht– *the doll sleeps not

• In English, these constructions will not look like the adult equivalents until the auxiliary system is acquired

Parameters

• So that parameter captures a lot of cross-linguistic variation, as well as some facts about language acquisition

• The “verb movement parameter”• Lexical verbs can either move, or they can’t• If they can (French, German), adult-like negation and

question formation will be acquired earlier• If they can’t (English), adult-like negation and

question formation will not be acquired until the auxiliary system matures

Our questions:• How do children develop such a system?

– Interaction between principles (universals) and parameters (limited variation, determined by exposure to linguistic environment)

• How much of this framework do they bring to the language acquisition situation? (i.e., how much is innate?)– The principles are innate; the parameters are present but unset; possibly also some

specific statistical learning procedures, an organizational framework, structural properties of the lexicon

• How much do they have to learn?– Which way parametric properties go; lexical and phonological properties of the

system• HOW do they learn this?

– Exposure, statistical algorithms, specific (?) learning mechanisms, domain general (?) learning mechanisms