1. Lexical Development II: Word spurt
Aylin Küntay
Language and Communication Disorders
Meeting 3

2. To know a word means
To link word (sound sequence) with meaning or concept
Symbol: refers to or stands for something
Quine’s induction problem: when someone point to a rabbit and say ‘rabbit’ how do you know the word refers to the animal and not the action of the rabbit or characteristics of the rabbit (white, fast, fluffy, big, etc.)
GAVAGAI PROBLEM

3. The very beginning of words
Around months. Are they ‘true’ referential words?
Many first words are context bound, situational, for e.g., doggie refers to dog sticker by the child’s bed
A word that is context bound for one child may be referential for another
Context bound usages are usually most frequent use by caregivers
Perhaps context bound words are not true words; we can talk about a prelexical stage of word learning
But some children’s first words are referential
Nelson: referential vs. expressive children

4. Acquisition of first 50 words
Slowly adding words until 18 months (range: months)
Add 8-10 per month, and sometimes new words do not stay around
Once the child knows words, the rate of word learning increases to around 40 words per month

5. Vocabulary spurt: Universal?
Some studies suggest no
Others suggest yes, but just occurs later (e.g., after the 50 word period)

6. Causes of vocabulary spurt
Ability for fast mapping
Could you please get the caponata?
Mervis & Bertrand: 4 familiar objects (ball, shoe, car, doll) and garlic press.
Give me the shoe vs. give me the dax
Children who fast mapped had larger vocabs
Naming insight. All things have names (Helen Keller)
Cognitive changes
Social skills development

7. Cognitive changes and vocabulary spurt
Nelson: change from analyzing experiences to things
Gopnik: development of categorization. Strong correlation between vocabulary and spontaneous two-category sorting
15 months: pick dolls, leave cars
18 months: make 2 piles of dolls and cars

8. Individual differences in rate of lexical development
Macarthur CDI. 16 months produce between months produce
Huge variability
Child factors
Environmental factors

9. Child features influencing rate
Phonological memory
At 4 years, children with bigger phonological memories learn more words even when controlled for IQ and vocabulary size
Sex differences (tiny difference): female advantage
Girls mature faster
Structural differences in brain
Caregivers talk more to girls

10. Environmental influences
More talk leads to more words
SES: Hart & Risley. Small effect but increases with time.
Birth order.
First borns reach 50 word mark earlier
But no difference at 100th word mark

11. Baldwin: interpersonal understanding
Importance of social interaction and interpersonal understanding
vs. Importance of salience (general cognitive constraints)
Evidence for importance of social interaction
Young typical babies
Autistic children

12. For Thursday
Simple sentences and Complex Syntax, Chapter 6 and Chapter 7 of How Babies Talk