At about 14 or 15 years of age, we see the development of more adult speech due to contacts beyond the home and school. During adolescence language use changes rapidly because of the dense social networks that teenagers form (Chambers, 1995:8). Then, in young adulthood, use of the standard form of language increases for those involved in occupations which are "language sensitive" (Chambers, 1995:159). However, another view is that children as young as four demonstrate social and stylistic variation even before they master the pronunciation and grammar of their language. (Labov 1989:96). This would suggest that variation occurs as part of the development of linguistic competence.

Some features of speech are characteristic of both language development and non-standard varieties. For example, young children may use alternative forms of the past tense that are also commonly used by mature speakers of non-standard varieties, as in "Meg done it". Teachers may, therefore, interpret the presence of these features in their student's speech in different ways. For example:

• They might see these features as indicating immaturity if the child young is or as indicating poorly developed speech if the child is older (i.e., that it is a developmental problem).
• They might see these features as characteristic of deficient language skills (i.e., as evidence of non-standardness and therefore as a linguistic problem). (Haig, 2001)

The development of language involves the development of speaking, reading and writing. But the development of specific oral language skills impact on success in reading and writing. Specific oral skills also impact on the ability to deal with the communicative demands of the classroom and the specific requirements of classroom discourse.

Language and Cognition