This study examined the effect of socio-economic status (SES) on the language and gesture use of 8- to 18-monthold infants, using two large, demographically diverse samples of children living in the UK and Poland. There was no systematic evidence for slower vocabulary or gesture growth in children from lower SES families in either sample, suggesting that substantial SES-related differences in language development do not emerge until after the first year of life.
Rowland et al. (Wed,) studied this question.