Bereiter & Engelman - Language used in working-class homes is deficient, and are more likely to communicate with gestures, single words and disjointed phrases. This acts as a barrier in schools; working-class children struggle with reading and writing.
Bernstein - He argues that there are two types of speech codes; 1) Restricted code - limited vocab, short and unfinished sentences, grammatically simple, use of gestures, context-bound assuming the listener shares the same experiences, spoken by the working class. 2) Elaborated Code - wider vocab, longer and grammatically more complex sentences, context-free and does not assume the listener has shared the same experiences, spoken by the middle class. The middle class have an advantage as schools (teachers, textbooks, exam papers) use the elaborated code, whereas working-class are disadvantaged as they can't access what is going on in the classroom.