Lecture Three

Lexical and Semantic Development

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.

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.

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.

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.

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.

First words …

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

First words …

• Entities

• Properties

• Actions

• Personal-social

First words …

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

Word classes …

• Nouns• Verbs• Adjectives

• Concrete nouns• 5-7 years: abstract

nouns begin to be used.

Word classes …

• Grammatical function words: noticeably absent in the early stages of lexical acquisition.

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.

Over-extension …

• Another common semantic error. Opposite of under-extension.

• A word is given a broader (more general, over extended) meaning.

Overextension …

• ‘daddy’ for all men, rather than just the child’s father.

• ‘dog’ for all four-legged animals.

Over-extension …

• More common: than under-extension.

• 50 word vocabulary: one third are likely to be overextended.

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.

Understanding …

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

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

Packaging Exploring 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

New vocabulary …

• GRAMMATICAL FUNCTION WORDS

• UNDEREXTENSION

• OVEREXTENSION

• LABELLING

• PACKAGING

• NETWORK BUILDING