Children’s lexical development is guided by properties of the speech they hear (nurture)
Children’s first words reflect their experiences. In answering the question of why are some words context bound and others referential, it could be that limited experience produces limited understanding. Children seem to not make use of the full range of their linguistic experience. For example, in one study researchers looked at how mothers used certain words and whatever context the mother used them in, the child used it the same way.
The culture in which a language is used shapes input and affects vocabulary development. Children’s first words are generally nouns in English whereas in Korean, Japanese, and Mandarin, first words consist more of verbs since the grammar of these languages allow noun dropping making verbs more frequent in the input. American mothers spend a lot of time labeling objects for their babies, whereas Japanese mothers were less likely to (Fernald and Morikawa, 1993).
Children who hear more speech and with richer vocabulary are able to build their own vocabularies at a faster rate than those who have less language exposure. Children from high SES backgrounds are generally more exposed to a richer vocabulary than low SES backgrounds.
First-borns are have slightly larger vocabularies due to more one-on-one interaction than later-born children. Mother-child interaction is correlated with children’s subsequent vocabulary development.
Children’s lexical development is guided by internal properties of children’s minds (nature)
Underlying changes in the nature of children’s phonological systems contribute to the word spurt. It has been proposed that the critical change comes from ongoing cognitive development and that many changes in word learning abilities occur after word learning begins with the result that word learning becomes increasingly efficient.
The “looking while listening” technique measures how quickly children looks to the correct picture when they hear a word. The ability to rabidly process words in speech is a predictor of future lexical growth.
Differences in producing context bound words in early lexical development reflect differences in their approaches to language acquisition. Some children may be more analytic than others. For example, dividing the speech stream into small parts whereas other children learn in a more holistic manner and acquiring big chunks.
The extent to which children are risk takers. While some children may talk without understanding the meaning of what they are saying, others may be more cautious and not using a word until certain they know the meaning of. Cautious children produce fewer context bound words.
Another difference that determines differences in the use of context bound words and referential words is sociability. A child who is interested in social interaction may want to use vocabulary words in certain situations, as well as, might be driven to use whatever means is available for interaction. These children are more likely to talk when their understanding of word meaning is still incomplete. A less social child may have little words that serve a social function and wait longer to talk.
Speed of language processing and phonological memory have relations to the rate of development.
Studies have found girls to be more advanced in vocabulary development than boys. May be because mothers talk to girl babies than to boy babies.