1 Language Development Gaia Scerif Room 426, Ext Office Hours: Thurs 12-2

2 Lecture List - 5th November (Dr. Scerif): Revision and introduction to theories of development 11th November (Prof. O’Malley): Language acquisition: Nativist approaches 12th November (Prof. O’Malley): Language acquisition: Socio- interactionist accounts 18th November: Video – Theories of language acquisition 19th November (Dr. Pitchford): Influences on language acquisition: The effects of sensory deprivation 25th November: (Dr. Pitchford): Stage theories of language development: Literacy 1 26th November (Dr. Pitchford): Stage theories of language development: Literacy 2 2nd December (Dr. Pitchford): Conceptual development: The case of colour cognition 1 3rd December (Dr. Pitchford): Conceptual development: The case of colour cognition 2 9th December (Dr. Scerif): Review of theoretical issues

3 Learning objectives * Theories of language acquisition 1. Developmental course of language acquisition? By what age / in what sequence do particular language abilities develop? 2. Driving force behind language development? Mechanisms responsible for developmental changes in children’s language abilities? 3. In what sense are our language abilities innate? To what extent is linguistic knowledge wired directly into the brain? To what extent does it develop as a function of the interaction between innate learning mechanisms and the structure of the environment?

4 Developmental Course of Language Acquisition Pre-speech Sounds (0 to 16 weeks) Vocal Play (16 weeks to 6 months) Babbling (6 to 10 months) Single Word Utterances (10 to 18 months) Two-word Utterances (18 months) Telegraphic Speech (2 years) Full Sentences (2 years 6 months) Vegetative sounds, Cooing, Laughter First speech-like sounds - Vowels (a e i o u) before Consonants (c, g, t) Strings of consonant vowel syllables (e.g. Bababa, Gugugu) Child uses small repertoire of single words (e.g. Mummy, doggie, more, gone) Onset of multi-word speech - correlated with sharp increase in vocabulary size Multi-word speech with many grammatical elements missing (e.g. Adam kick ball, Dolly not like it, What doing?) Multi-word speech with more and more of the grammatical elements included (e.g. I’m kicking the ball, Dolly doesn’t like it; What are you doing?)

5 What drives language development? The Role of Imitation Imitation obviously has a role to play in language development. However: 1. From early in development children produce utterances that they could never have heard: Word class errors: More read, Other one spoon, That’s a pretty Case-marking errors: Me can do it, Him like it, Her has a tummy ache Morphological overgeneralisations: Two sheeps; She holded the rabbits; They went to the graveyard and unburied her Argument structure errors: Don’t say me that, This jumper sweats me, Stay your eye on that car in front; I’m pouring him with water

6 What drives language development? The Role of Imitation Imitation obviously has a role to play in language development. However: 2. Children unable to imitate utterances they cannot spontaneously produce De Villiers & De Villiers (1979) Child: Kurka Adult: Turtle. Say “Tur” Child: Tur Adult: Say “Tle” Child: Tle Adult: Say “Turtle” Child: Kurka Braine (1971) Child: Want other one spoon Adult: You want the other spoon? Child: Yes. I want other one spoon Adult: Can you say “the other spoon”? Child: Other … one … spoon Adult: Say “Other” Child: Other Adult: “Spoon” Child: Spoon Adult: “Other … spoon” Child: Other … spoon. Now give me the other one spoon

7 Learning Theory (Skinner, 1957) Language development as a process of learning by shaping and reinforcement. Child’s language learning as analogous to the learning of a rat in a Skinner box: 1. Rat happens to depress a lever in the presence of a particular stimulus (e.g. a light or tone) 2. Lever press is reinforced (e.g. by the provision of a food pellet) 3. Rat is said to be conditioned by reinforcement to depress lever in the presence of the tone 4. By selectively reinforcing only certain types or sequences of lever presses, rat’s behaviour can be shaped into more and more complex sequences of responses

8 Language learning as conditioning 1. Child babbles or imitates sound pattern made by adult in presence of particular stimulus (e.g. produces ‘Wa(nt)’ when hungry) 2. Adults reinforce child’s verbal behaviour (e.g. respond to ‘Wa(nt)’ by providing food) 3. Child conditioned through positive reinforcement to emit sound pattern more often in presence of that stimulus (e.g. produces ‘Wa(nt)’ more often when hungry because this behaviour results in provision of food) 4. Child’s speech sounds shaped by selective reinforcement until producing adult-like words (e.g. ‘Wa(nt)’ becomes progressively more like ‘Want’ as adult becomes progressively more demanding about the sound patterns she will respond to) 5. If it is assumed that each word can act as a stimulus for the next, sentences can be built up as sequences of learned responses (e.g. Child learns to say ‘Want milk’ by producing ‘Want’ as conditioned response to its own hunger and ‘Milk’ as conditioned response to the word ‘Want’)

9 Empirical Problems 1. Parents do not provide consistent enough feedback for children to learn language this way. Brown & Hanlon (1970) showed that parents tend to respond to children’s utterances on the basis of their truth value rather than their grammatical correctness Child: That’s a doggie (pointing at a horse) Adult: No, that’s a horsie (stressed) Child: We goed in the park Adult: That’s right. And we fed the ducks, didn’t we? Parents reinforce ungrammatical utterances if true and reject grammatical utterances if false

10 Empirical Problems 2. Children are often resistant to correction even when it does occur Child: Nobody don't like me Adult: No, say “nobody likes me” Child: Nobody don't like me. Adult: No, say “nobody likes me” Child: Nobody don't like me. Adult: No, say “nobody likes me” Child: Nobody don't like me (8 times) Adult: No. Now listen carefully. Say “nobody likes me” Child: Oh! Nobody don't likes me Negative feedback not the major driving force in grammatical development

11 U-shaped pattern of development After a period of correct production, children’s performance declines as they begin to make over- generalisation errors, before improving again Phonology Turtle *Kurka Turtle Morphology Went *Goed Went Argument Structure Say that to me *Say me that Say that to me From an early age, children seem to be learning rules and exceptions to rules

12 Chomsky’s Critique Learning theories cannot explain the development of language because they start out with a false description of what language is like: 1. Language cannot be analysed into simple associations between stimuli and responses What stimulus controls the verbal responses ‘Blair’ or ‘Afghanistan’? How easy is it to tell what a person will say in response to the clock striking twelve? 2. Language has underlying structure that cannot be explained in terms of learned sequences of responses Sentences are not strings of words but hierarchical structures into which words can be inserted as a function of their place within a system of rules

13 Summary 1. Early theories of language development attempted to account for language learning in terms of general processes such as imitation and conditioning through reinforcement 2. Such theories not consistent either with what we know about children’s language-learning environments or with the developmental sequence in which their linguistic abilities unfold 3. Critique of learning theory approaches: Chomsky argued that they could not explain the development of language because they started out with false view of what language was like 4. Chomsky: the nature of language is such that it could only be acquired if the child already had a great deal of innate domain- specific knowledge about the way language works

14 Nativism: Language Genes? Can genetic variability specify and determine language development?

15 Can genetic variability specify and determine language development? Nativism: Language Genes?