Basil Bernstein (1971) introduced the notion of the Restricted and the Elaborated code, claiming that working-class speakers have access only to the former but middle-class members to both. In an attempt to test this theory in the Iranian context and to investigate the effect of social class on the quality of students language use, we examined the use of six grammatical categories including noun, pronoun, adjective, adverb, preposition and conjunction by 20 working class and 20 middle-class elementary students. The results of Chi-square operations at p<0.05 corroborated Bernstein's theory and showed that working- class students were different from middle-class ones in their language use. Being consistent with Bernstein's theory, the results obtained for the use of personal pronouns indicated that middle-class students were more person-oriented and working-class ones more position-oriented. Findings, thus, call for teachers' deliberate attention to learners' sociocultural variation to enhance mutual understanding and pragmatic success.