Development of Language: Intro
15 months: 25 word vocabulary 5 years = 10-15, 000 words.
Foundations of Language: Rationalism and Empiricism
Philosophy has produced two contrasting views on how humans obtain knowledge. Is knowledge acquired through the senses? Or is it innate?
Rationalism and Empiricism People
Rationalist: Plato and Descartes
Empiricist: Locke and Hume
Rationalism and Empiricism: Nature vs Nurture
Rationalist: Fundamental knowledge is innate, favours nature rather than nurture
Empiricist: All knowledge derives from experience, favours nurture in nature v nurture debate
Rationalism and Empiricism: Birth and Tabula Rasa
Rationalist: Language capacity is present from birth
Empiricist: Locke - All knowledge can be acquired through experience. The newborn is a 'tabula rasa' (a blank slate) upon which sensations write and determine future behaviour
Rationalism and Empiricism: Chomsky and Piaget
Rationalist: Chomsky - language is innate. Humans are born with hard-wired principles that determine the class of possible languages we can learn: universal grammar
Empiricist: Piaget - language ability follows cognitive development. Cognitive precursors. Cognitive structures are not innate, but can arise from innate dispositions.
What drives language acquisition? Be Careful
It is not wise to split the answer to the question "what drives language acquisition" like this. It is more likely to be a combination of the two because language development is a complex process that involves the development of many skills, and processes that may be important for syntactic development.
Theories of Language Development
Imitation: Mistakes, Grammatical Construction, Other Areas
Can not by itself be a primary driving force of language development, and particularly of syntactic development. Children make mistakes that adults do not, so it can't be real imitation. Furthermore, when children try to imitate what they hear, they are unable to do so unless they already have the appropriate grammatical construction. Imitation of adult speech (and that of other children) plays an important role in acquiring accent, the manner of speech, and in the choice of particular vocabulary items.
Just reinforcement and conditioning?
Learning Theory Criticisms
1. Adults correct mainly the truth and meaning of a child's utterances, rarely the syntax 2. Some words are understood before they are produced 3. The pattern of acquisition of irregular past tense verbs and irregular plural nouns is u-shaped 4. Aspects of the structure of language means it cannot be acquired simply by conditioning 5. In phonological production, babbling is not random and imitation is not important
1. Adults correct truth and meaning, not syntax
Adults (generally) correct only the truth and meaning of children's utterances, not the syntax. e.g. Child: she holded the baby rabbit Adult: did you say she held them tightly? Child: no she helded them loosely. Attempts by adults to correct incorrect syntax and phonology usually make no difference. Parents rarely correct grammar and if they try to do so the corrections have little effect. Brown (1973): Truth value rather than syntactic well-formedness chiefly governs explicit reinforcement by parents.
Sentences such as "her curl my hair" are not corrected whereas "Walt Disney comes on tuesday" is corrected.
1. Gramatically correct, culture
Parents are more likely to repeat the child's incorrect utterance in a grammatically correct form, or to ask a follow-up question. On the other hand, if the child's utterance is grammatically correct, the adults just continue the conversation (Messer, 2000). People from different cultures also respond differently to grammatically incorrect utterances, with some appearing to place more emphasis on correctness.
1. Developmental change
Some argue that occasional contrast between the child's own incorrect speech and the correct adult version does enable developmental change (Saxton, 1997). Evidence in favour of this is that children are more likely to repeat adults' expansions of their utterances than other utterances, suggesting that they pay particular attention to them (Farrar, 1992).
1. Negative Evidence
The debate about whether or not children receive sufficient negative evidence (such as information about which strings of words are not grammatical) is important because without negative feedback children would have to rely on mechanisms such as innate principles to help them learn the grammar.
2. Understanding before production
The second piece of evidence against a conditioning theory of language learning is that some words (such as "no!") are clearly understood before they are ever produced.
The pattern of acquisition of irregular past verb tenses and irregular plural nouns cannot be predicted by learning theory. Some examples of irregular forms given by children are "gived" for "gave", and "mouses" for "mice"; Ovegeneralisation like "Bringed and goed (past tense rules) and feets and sheeps (plural rule). The sequence observed is: correct production, followed by incorrect production, and then later correct production again, producing a U-Shaped curve. Performance starts off at a good level, but then becomes worse, before improving again.
An explanation for this pattern is that the children learn a general rule (e.g. "form past tenses by adding '-ed'") but apply it incorrectly by using it in all instances. Only later do they learn the exceptions to the rule. Children can begin by using the correct form but lose it once they have constructed their rule. U-shaped development is suggestive of a developing system that has to learn both rules and exceptions to those rules. Different syntactic rules at any stage of development seem to govern the construction of a child's sentence.
4. Not just conditioning
Chomsky (1959) argued that theoretical considerations of the power and structure of language means that it cannot be acquired simply by conditioning.
5. Babbling and Imitation
Babbling is not random, and imitation is not important: the hearing babies of hearing-impaired parents babble normally.
Theories cannot account for...
Non-random mistakes; speed of acquisition of basic grammar rules; learning without formal instruction; regularity of learning patterns across cultures and languages.
It has been proposed that a child must be actively engaged in determining the rules of their language. In general, language development appears to be strongly based on learning rules rather than simply learning associations and instances.
Poverty of the Stimulus - Input Alone
Chomsky argued that children cannot learn the rules of their grammar (linguistic rules) by input alone because the input is inadequate in 2 ways
Poverty of the Stimulus - Degnerate
1) Degenerate input: The speech children hear is full of slips of the tongue, false starts and other dysfluencies and mispronunciations. Words not clearly separated
Poverty of the Stimulus - Insufficient
2) Insufficient: There is not enough information in the language children hear for them to be able to learn the grammar (i.e. they are not exposed to enough examples of grammatical constructions to work out the underlying rules). They do not hear defective sentences that are labelled as effective.
CDS and Distributional Information
The first part of Chomsky's claim is controversial because of research involving CDS. This special way of talking to children was originally called motherese, but is now called child-directed speech (CDS for short), because its use is clearly not limited to mothers. It is commonly known as "baby talk".
CDS - Simples
Adults talk in a simplified way to children where speech is easily recognisable; topics relate to the here and now; short sentences which are phonologically simplified; exaggerated prosody; slow clearly segmented speech; lots of repetition; pitch higher to gain attention; pauses; facial expression and uses emphasis on important words.
CDS - Useful For
This can be useful for: build social intent and framing interaction; feedback (of needs) and conversation; focus on salient objects facilitates language and also the bond between mother and child.
CDS - Required, Culture, Development
Do children require a syntactically and phonologically simplified input in order to be able to acquire language? Research thinks not. CDS also does not occur in all cultures. Cultures may simplify language in other ways like with an emphasis on social interaction. Rate of linguistic development is not correlated with the complexity of the children's input. Even though CDS might not be necessary for language development, it might nevertheless facilitate it.
The degenerate and improvised input children receive may still contain sufficient information. There is evidence that children can derive regularities from the distribution information in speech e.g., sound structure, syntactic structure.
Language Acquisition Device (LAD) - What might be innate in Language?
Chomsky considered it to be impossible that a child could deduce the structure of the grammar solely on the basis of hearing normal language. Something additional is necessary. He argued that the additional factor is that the design of the grammar is innate: some aspects of syntax must be built into the mind.
LAD - Chomsky
Language acquisition must be guided by an innate device which he called the LAD or Universal Grammar (UG), which provides the rules and principles that allow a child to learn any natural grammar.
LAD - Chomsky
For Chomsky, language is not learned, but grows. Chomsky views language acquisition as a process of acquiring a grammar, the basis of which is innate, acquiring a language involves putting the built in switches (parameters) into the correct positions. Languages differ in their structure and UG limits the number of hypotheses a child can form concerning the rules of their language.
LAD - Parameters
In some areas of language structure, UG provides a limited range of options or parameters which can be set (like a set of switches that constrain the possible shape of the grammars the child can acquire). The child's job is to determine from the input which parameter is appropriate for their language.
LAD - Parameters
Parameters set the core aspects of language. Different parameters are at different positions for different languages. The LAD sets boundaries for what acquired languages look like, they are restricted. Thus this approach sees language acquisition as parameter setting. This limits errors and explains speed of learning despite incomplete input.
LAD - Pro-Drop
Some language's you can just say "speaks" whereas in others you have to include the pronoun so the sentence reads "he speaks". Whether or not you can drop the pronoun is a parameter. English and French are not pro-drop languages whereas Italian and Arabic are pro-drop. When the pro-drop is specified, other aspects on language fall into place.
Evaluation - Slow, errors, continuity
The parameter process is slow and full of errors. Why does it take so long to set the switches? To save those errors, why not just set parameters straight away? Continuity hypothesis: all parameter principles are available from birth but affected by other factors. For example, the child needs to be able to identify words belonging to categories and have the memory capability.
Evaluation - Accessible and language
Another view is that all of the information is available from birth, but it is just not accessible. It becomes accessible gradually as the brain develops and matures. Another criticism is that it is difficult to find particular parameters set in different languages
Evaluation - Deaf Children
How do deaf children acquire sign language? Similar processes may underlie both sign and spoken language. The milestones in both languages occur at around the same time. Signing children make the same systematic errors as children at the same time. This shows that even sign language develops in a similar way to spoken language. It provides a problem for the theory in that it is unclear how sign language gestures can be matched to innate principles and parameters of verbal language.
Evaluation - Bilingual children
How can they acquire 2 languages when the languages might need different parameters set to different positions?
Chomsky lessened the importance of grammatical rules in the acquisition of language.
Stages of Language Development
Sound information is impoverished. Higher frequencies which allow us to distinguish individual sounds are blocked by amniotic fluid in womb
Can distinguish stories read to them in the womb. DeCasper and Spence (1986): sucking paradigm (prosody).
Early Speech Perception
Very young infants are predisposed to listen to speech sounds and are aware of fine distinctions between them. This is exampled through sucking modification paradigms.
In this procedure, experimenters measure the sucking rate of infants on an artificial teat. Babies prefer novel stimuli, and as they become habituated to the stimulus presented, their rate of sucking declines. If they then detect a change in the stimulus, their sucking rate will increase again. In this way it is possible to measure whether the infants can detect differences between pairs of stimuli.
Sucking Modification Results
It has been shown that from birth children are sensitive to speech sounds, as distinct from non-speech sounds. Infants between 1 and 4 months of age, and perhaps even younger, are sensitive to all the acoustic differences later used to signal phonetic distinctions e.g. voicing, place, and manner of articulation, prosody (e.g. preferring mothers voice)
Sensitivity to Language
Below 1 year: sensitive speech sound distinctions that occur in all languages. 12 months: sensitivity to foreign contrasts diminished significantly (if sounds not used in language into which they are growing up)
Early Speech Output
Vegetative sounds: Cooing: 6 Weeks; Laughter: 16 Weeks; Vocal Play: 16 Weeks - 6 Months; Babbling: 6-10 Months; Single Word Utterances: 10 - 18 Months; Two Word Utterances: 18 Months; Telegraphic Speech: 2 Years and Full Sentences: 2 Years and 6 Months
Reflexive, Meaning, Intonation
Throughout infancy, vocalisations develop from being automatic and reflexive vocalisations no meaning, to articulated words with meaning and intonation. Initially, vocalisation is reflexive. In response to the environment to elicit care and food, reflecting their current needs.
0-16 weeks: Vegetative Sounds
Vegetative sounds, crying, cooing, laughing. Stimulus controlled- involuntary response to emotional states
16 weeks: Vocal Play
Vocal play (up to 6 months). Speech like sounds. Vowel like sounds: ooh and aah. Desire to explore and develop new sounds like yells, squeals and whispers. Show a dialog structure stemming from motherese (CDS).
Babbling is distinguished from vocal play by the presence of true well formed syllables (consonants plus vowels), which often repeated over and over. May be used for communicative purposes as they get closer to saying their first words.
There are two types of babbling (Oller, 1980). Reduplicated babble is characterized by repetition of consonant-vowel syllables, often producing the same pair for a long time (e.g. "bababababa"). Non-reduplicated or variegated babble is characterized by strings of non-repeated syllables (e.g. "bamido"). Babbling lasts for 6-9 months, fading out as the child produces the first words. It appears to be universal: deaf infants also babble
Continuity hypothesis: babbling is a precursor of language. Babbling produces all sounds for language, these are eventually narrowed down and develops into language. However, many sounds like consonant clusters are not produced at all in babbling. Discontinuity hypothesis: babbling has no relation to later development.
Laura Pettito compared the vocal babbling of hearing children to the manual babbling of deaf children. Children have an innate predisposition to discover the units which serve to express linguistic meaning. Babies will produce these units depending on the input they have received.
Months - Single Word Utterances Slow at first followed by a rapid explosion in vocabulary size about 18 months. Children can learn new words for objects after only one exposure (fast mapping). When it comes to relating sounds to meaning, children are at the holophrastic stage which is just one word speech. Communicate complex ideas using only single words and simple fixed expressions. E.g. the word "food" might be used to mean "Give me food"
Words 3 functions
Words serve 3 functions: 1) Naming and reference 2) Linked to child's action or desire for it 3) Expressing emotional state
Word Meanings (Whole word constraint)
Present a new object and label it with a nonsense word (e.g. that's biff). Children take biff to refer to the whole object, not its colour, what it's made of or one of its parts.
There is evidence that children have certain predispositions when it comes to assigning meanings to chunks of sound. They assume a basic level category and learn basic level words sooner than superordinate words (acts as an 'umbrella' term that includes within it the meaning of other words) or subordinate words (a word that is more specific than a given word), (e.g. poodle<DOG>animal)
Assume that words refer to a category of similar things e.g. Dog's name = "Spot": use the word to refer to the neighbour's dog as well or all four legged animals.
Syntactic Clues to Word Meaning
Children can also use their knowledge of word formation rules and syntactic class to help them derive the meanings of words.
18 Months - Two word utterances
Clear syntactic and semantic relationships. No syntactic or morphological markers. No inflection for person/number/tense. One construction can serve several grammatical relations. There is evidence of regularities in the way particular children construct these utterances (i.e. rule driven). But determining the underlying principals is problematic: syntactic or semantic?
2 Years - Telegraphic speech
Number of words, many grammatical elements missing. No three word stage. Children with mean length of utterance (MLU) of 2.5-3.5 morphemes) seem to be at the stage of grammar acquisition
(MLU is counted by listening to 30 mins of the infant speaking, counting meaningful morphemes and dividing by number of utterances.
2 Years - Telegraphic speech
These first utterances tend to lack function words but have syntactic structure. They adhere to the word order restrictions of the language.
2 and a half - Full sentences
Following this stage grammatical function words and morphological inflections start to come. Innate syntax module or distribution analysis?
Phonological and Morphological Rules - Wug
Berko-Gleason (1958) demonstrated rule application
Shown a picture of a Wug, then two wugs. They replied with the correct plural term. It was designed as a way to investigate the acquisition of the plural and other inflectional morphemes in English-speaking children.
The child is presented with some sort of pretend creature, and told, "This is a wug." Another wug is revealed, and the researcher says, "Now there are two of them. There are two...?" Children who have successfully acquired the plural morpheme will respond: wugs and not something like "two wug" (young children did this). They applied the plural rule and also produced the correct phonological form (voiced/voiceless matching). About 4-5 year olds deal best with this.