Language minorities represent a marginalized group in education systems worldwide. This study examines the interplay between family language background, access to preschool, and reading achievement among students from families where the home language differs from the majority language of their country of residence. These issues align with the targets of the United Nations' Sustainable Development Goal 4, which aims to achieve equity in education. Our analysis uses data from the Progress in International Reading Literacy Study (PIRLS) collected in 16 countries between 2001 and 2021, comprising 314,068 students. The study is conducted in two steps. First, we investigate gaps in preschool access and reading achievement between students who speak the majority language at home and those who do not. Second, we analyze the impact of preschool attendance on reading achievement, focusing on the differential effectiveness of preschool for language minorities compared to language majorities. Additional analyses explore the intersectionality between family language and socioeconomic background. The findings reveal significant disparities in educational opportunities and outcomes to the disadvantage of language minority students. These students are less likely to attend preschool and more likely to lack basic reading skills. Preschool attendance significantly reduces the risk of lacking basic reading skills at the end of preschool. However, the effects are heterogeneous: preschool attendance has a strong positive impact on language minorities from socioeconomically disadvantaged backgrounds, while the effect is negligible for language majorities from socioeconomically advantaged backgrounds. In essence, preschool is particularly effective in supporting the acquisition of the majority language for language minorities, yet these students remain underrepresented in preschool settings.

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