Current approaches which deal with a possible mismatch between child rearing practices at home and education at school tend to focus either on family or institutional characteristics. The paper investigates the interplay of communication, socialization practices and educational opportunities by reconstructing discourse practices of the same children in different contexts: family dinner talk and classroom interaction. It, thus, reintroduces the notion of language “barriers” to the debate over educational justice. The selection of the children in the study took up results of international large-scale studies which indicate that different migrant groups differ in their participation in the German educational system. The analysis is based on a corpus of 72 naturally-occurring argumentative sequences of 6 year-old children with Vietnamese, Turkish and German as their first language during family dinner talk and 20 lessons of classroom discourse in German primary schools. The micro-analytic reconstruction demonstrates how discourse practices are socio-culturally situated and differ in terms of communicative genres, topics and communicative demands both between families and contexts. The analysis of classroom discourse shows that children differ in meeting institutional discourse expectations and in utilizing discourse as a means of learning.