This study is based on interviews with adolescents under conditions where the kinds of constraints which operate in more formal settings were minimised. Samples of the speech of twenty-four boys and girls aged between fourteen and a half and eighteen, from both urban and non-urban environments, were analysed, using sixteen measures derived from Bernstein's theories. Social class differences appeared on only three measures. This suggests either that forms of analysis primarily based on the structure of language are inappropriate, or that there are smaller social class differences in language use than would be expected on the basis of Bernstein's theories. This adds to the growing body of evidence that Bernstein's ‘research programme’ has moved into a degenerative phase.