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

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

3. 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?

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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

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

12. 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

13. W.r.t. disorders
Insight about naming

14. 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

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