Language Acquisition: Lecture 3 Lexical and Semantic Development

Language Acquisition

1. Lecture Three
Lexical and Semantic Development

2. Lexical and Semantic
Development …
•Lexical development = a child’s
acquisition of words.
•Semantic development = a child’s
acquisition of the meanings associated
with those words.

3. Be careful …
•REMEMBER : vocabulary acquisition
does not end at a certain age. We continue
hearing and learning new words and their
meanings throughout our lives.

4. Rate of acquisition …
•End of first year: child begins to speak.
•18 months: vocabulary of about 50 words.
•2 years: vocabulary of about 200 words.
EXPLOSION!!!
•5 years: vocabulary of 2000 words.
•7 years: vocabulary of 4000 words.

5. Understanding …
•The previous figures refer to word use.
•At each stage, the number of words
understood by the child is expected to be
higher.
•18 months: 250 words understood.

6. Meanings …
•When a child adds a new word to their
vocabulary, they are not immediately
aware of its full range of meanings.
•More time is required to acquire this
additional knowledge.

7. First words …
•Research has shown
that there are
predictable patterns
in the words and word
classes first acquired
by children.

8. First words …
•Entities
•Properties
•Actions
•Personal-social

9. First words …
•Predictably, a large
proportion of a child’s
first words refer to
familiar people,
objects and aspects of
social interaction.

10. Word classes …
•Nouns
•Verbs
•Adjectives
•Concrete nouns
•5-7 years: abstract
nouns begin to be
used.

11. Word classes …
•Grammatical
function words:
noticeably absent in
the early stages of
lexical acquisition.

12. Under-extension …
•Common semantic
error made by
children.
•A word is given a
narrower (under
extended) meaning.
•‘cat’ is the family pet,
but not other cats.

13. Over-extension …
•Another common
semantic error.
Opposite of under-
extension.
•A word is given a
broader (more
general, over
extended) meaning.

14. Overextension …
•‘daddy’ for all men,
rather than just the
child’s father.
•‘dog’ for all four-
legged animals.

15. Over-extension …
•More common: than
under-extension.
•50 word vocabulary:
one third are likely to
be overextended.

16. Getting it right …
•Age 2 ½ : marked decrease in number of
overextensions.
•Explanation: child’s vocabulary is
increasing rapidly, thus filling the gaps
previously filled by overextended words.

17. Understanding …
•REMEMBER : children’s understanding
of word meanings is ahead of their ability
to produce the corresponding words.

18. Aitchison (1987) …
•Three stages/processes occur during
acquisition of vocabulary:
Labelling Linking words to the objects to which they
refer Understanding that objects can be labelled
PackagingExploring what labels can apply to. Over/under
extension occurs in order to understand the range
of a word’s meaning
Network
building
Making connections between words –
understanding similarities and
opposites in meanings

19. New vocabulary …
•GRAMMATICAL FUNCTION WORDS
•UNDEREXTENSION
•OVEREXTENSION
•LABELLING
•PACKAGING
•NETWORK BUILDING