Lexical and Semantic Development: Part 1 Aylin Küntay Language and Communication Disorders Meeting 2

Announcements Reader should be ready by Friday or Monday Finish Chapter 5 in “How babies talk” by Tuesday

Early words Lexical development: the study of the development of vocabulary Semantic development: the study of the development of meaning the two are very much interlinked what is the scope of meaning of early words? how are prelinguistic meanings mapped onto words?

Lexical development Clark, Carey: children start building their vocabulary at around 18 months, on average, adding 10 new words a day! Age for “first words” is earlier Collected in diary studies and checklists that include words that the children are likely to acquire and that are filled out by parents MacArthur Communicative Development Inventory (CDI) Or diary studies moms can conduct Or direct longitudinal recording of some children

What kinds of words are first words? Bates et al.: nearly 40% of average child’s first 50 words are common nouns verbs, adjectives, and function words each account for less than 10% How about research in non-English languages? Gopnik, Choi & Baumberger about an English vs. Korean comparison Korean children have as many or more verbs in their early speech Noun bias vs. verb bias languages

Why a noun bias? Why should nouns be acquired more rapidly than other types of words? Gentner: the concepts referred to by nouns are clearer, more concrete, and more readily identifiable than the concepts referred to by verbs (natural partitions hypothesis) verbs are conceptually and linguistically more complex (relational relativity hypothesis) Walk, run in Eng. Vs. Exit, Enter in Spanish Clark, Naigles: early verbs tend to be general-purpose verbs such do, make, go, and get Goldfield: child-directed speech has a bigger range of nouns (i.e., object labels) than words for activities, properties, or relations

Noun bias: challenges Bloom, Gopnik: early words also include lots of relational words such as gone, up, there, more, uh-oh, again and social/performative words such as hi, bye some of these are actually predicates (i.e., verbs) Nelson: referential vs. expressive styles cross-linguistic challenges

Cross-linguistic studies Tardif (Mandarin Chinese), Gopnik & Choi (Korean), Clancy, Fernald (Japanese) these languages are different than English rich verbal morphology, verb-final, allow noun ellipsis (i.e., dropping) where context is clear Korean& Japanese-speaking mothers used fewer nouns than English-speaking mothers Kor and Jap children use verb morphology earlier than English-speaking children but use fewer and less varied names

One-word utterances: ¨Holophrases¨ one-word utterances are used with communicative intent parents place interpretations on one-word sentences such as up as ¨take me up¨ how can we attribute meaning to such brief and unstructured utterances? What are the communicative functions of these utterances? RICH INTERPRETATION Daddy when pointing to a picture of daddy ==> NAMING after finding daddy’s tie ==> POSSESSION offering bottle to daddy ==> DATIVE, GOAL one-word utterances express underlying relational notions

Overextensions and Underextensions Unconventional word/meaning mappings Overextension: when a child uses a word in a context or manner that is inconsistent with, but in some way, related to, the adult meaning of the word term is extended to concepts beyond the adult concept daddy for adult men cat for all four-legged animals bye-bye to greet visitors Underextension: when a child uses a word for only a limited subset of the contexts used by the adult cat for the home pet only truck for the toy truck only

Word spurt? (next time) What is it? Does it exist universally? How can it be explained if it exists?

Individual differences in rate of word learning Big! Need to understand because of theoretical and practical reasons Environmental factors: CDS-related factors such as birthorder, maternal speech (education) Child factors: earlier joint attention skills (Carpenter at al.), better phonological memory (Gathercole and Baddeley), temperament (Slomkowski, Nelson, et al.), sex differences

W.r.t. disorders Insight about naming

Conditions for vocabulary development Intention to mean Reference to a general category Moving closer to the adult phonological form Systematic and consistent usage of work

Cause for worry Input conditions are as desired AND By 18 months no production of words Not many words comprehended