PSY 369: Psycholinguistics Language Acquisition: Learning words, syntax, and more

Learning word meanings Learning words (a brief review) One word stage Idiomorphs Over and under extension of meaning Generally: one word per referent If it doesn’t work, pick a new word How do the kids match the words to the referents?

Indeterminacy: Frog Frog Frog? Green? Ugly? Jumping?

Quine’s gavagai problem The problem of reference: a word may refer to a number of referents (real world objects) a single object or event has many objects, parts and features that can be referred to Frog Frog? Green? Ugly? Jumping?

Constraints on Word Learning Perhaps children are biased to entertain certain hypotheses about word meanings over others These first guesses save them from logical ambiguity get them started out on the right track Markman (1989) Object-scope (whole object) constraint Taxonomic constraint Mutual exclusivity constraint

Object-scope (whole object) constraint words refer to whole objects rather than to parts of objects Strategies for learning

‘Show me another lux’ ‘Here is a lux’ Taxonomic constraint words refer to categories of similar objects taxonomies rather than thematically related obejcts Strategies for learning

But in ‘no-word’ conditions, they would be shown the first picture See this? Can you find another one? Strategies for learning

they choose the corkscrew because it is a less well known object for which they don’t have a label yet. ‘Show me a dax’: Mutual exclusivity constraint (Markam and Watchel 1988) each object has one label & different words refer to separate, non-overlapping categories of objects an object can have only one label Strategies for learning

Problem with constraints Most of the constraints proposed apply only to object names. What about verbs? (Nelson 1988) There have been cases where children have been observed violating these constraints using for example the word ‘car’ only to refer to ‘cars moving on the street from a certain location’ (Bloom 1973) The mutual exclusivity constraint would prevent children from learning subordinate and superordinate information (animal<dog<poodle)

The language explosion is not just the result of simple semantic development; the child is not just adding more words to his/her vocabulary. Child is mastering basic syntactic and morphological rules. Language explosion continues

Proto-syntax (?) Holophrases Single-word utterances used to express more than the meaning usually attributed to that single word by adults Language explosion continues “dog” might refer to the dog is drinking water May reflect a developing sense of syntax, but not yet knowing how to use it Controversial claim (e.g., see Bloom, 1973)

Syntax Remember: word order is important! Basic child grammar (Slobin, 1985) Similarities across all languages Mean length of utterance (MLU) in morphemes Take 100 utterances and count the number of morphemes per utterance Language explosion continues Daddy coming. Hi, car. Daddy car comed. Two car outside. It getting dark. Allgone outside. Bye-bye outside. # morphemes: 3, 2, 4, 3, 4, 2, 2 ‘-ing’ and ‘-ed’ separate morphemes ‘allgone’ treated as a single word MLU = morphemes/utterances = 20/7 = 2.86

Language explosion continues

Syntax Roger Brown proposed 5 stages Stage 1: Telegraphic speech (MLU ~ 1.75; around 24 months) One and two word utterances Debate: learning semantic relations or syntactic (position rules) Similar meaning to words used in 1 word stage: Negation, nonexistence, call attention Soon branches out to other meanings (Brown, 1973) Language explosion continues Children in telegraphic speech stage are said to leave out the ‘little words’ and inflections: e.g. Mummy shoe NOT Mummy’s shoe Two cat NOT two cats

More than two words Stages 2 through 5 Stage 2 (MLU ~2.25) begin to modulate meaning using word order (syntax) Later stages reflect generally more complex use of syntax (e.g., questions, negatives) Language explosion continues Syntax Roger Brown proposed 5 stages

Innateness account Pinker (1984, 1989) Semantic bootstrapping How do kids learn the syntax? Child has innate knowledge of syntactic categories and linking rules Child learns the meanings of some content words Child constructs some semantic representations of simple sentences Child makes guesses about syntactic structure based on surface form and semantic meaning

“It is in the stimulus” accounts Children do not need innate knowledge to learn grammar Speech to children is not impoverished (Snow, 1977) children learn grammar by mapping semantic roles (agent, action, patient) onto grammatical categories (subject, verb, object) (e.g. Bates, 1979) How do kids learn the syntax?

Morphology Typically things inflections and prepositions start around MLU of 2.5 (usually in 2 yr olds) Wug experiment (Berko-Gleason, 1958) Language explosion continues Here is a wug. Now there are two of them. There are two _______.

Morphology Lists of forms Rules Overregularization Language explosion continues