The Role of Older Siblings in Language Learning in Migrant and Non-Migrant Families

Language skills are key to educational success. However, family social and migration backgrounds often contribute to disparities in children's language abilities, leading to educational inequalities. While most research has focused on primary caregivers, showing that parental resources, language proficiency and interactions predict children's language outcomes, less is known about the role of siblings. In Western societies like Germany, around 75% of children grow up with siblings, yet their influence on language learning remains comparatively understudied.

Previous research suggests that larger sibship size negatively affects cognitive and educational outcomes due to resource dilution, i.e., limited parental time and material resources or a reduced intellectual family climate. However, previous studies also indicate that older siblings can enhance younger siblings' communication skills, though the effects may vary by sibling gender. For example, older sisters tend to be beneficial, while older brothers can be detrimental. In foreign language-speaking families, a positive, though not statistically significant, effect of older siblings was found, highlighting the potential for supporting second language learning.

This study extends this line of research by examining whether older siblings play a stronger role in migrant children’s language learning. We theorize that older siblings can promote second language learning through various mechanisms, such as everyday communication, particularly in families where they compensate for parents' limited usage and proficiency in the target language. Using data from the German National Educational Panel Study (NEPS), we analyze cohorts in lower secondary (grade 5) and upper secondary school (grade 9) to assess older siblings’ role at different developmental stages. Preliminary multivariate regression results show an overall negative effect of older siblings on vocabulary and reading skills. In some cases, these trends are less pronounced—and tend to be positive—for migrant children, e.g., in lower secondary school, for first-generation migrants in vocabulary and for second-generation migrants in reading.