Dialects matter: The influence of dialects and code-switching on the literacy and numeracy achievements of isiXhosa Grade 1 learners in the Western Cape

African languages have been historically disadvantaged and issues of dialects are not fully understood and acknowledged. The current study examined the effects of dialects and code-switching on the literacy and numeracy achievement of isiXhosa Grade 1 learners, when controlling for other factors such as between school variance, socio-economic status and gender with multi-level modelling. The project used stratified random sampling to select Afrikaans, English and isiXhosa schools in three districts in the Western Cape. A total of 2 497 learners were assessed, of which 768 learners were in isiXhosa schools. Dialects and code-switching to another language had a significant, negative impact on both literacy and numeracy scores for isiXhosa learners. The findings highlight the importance of investigating dialectic issues in isiXhosa. Decolonisation of African languages require the development of resources within the languages for classrooms, strengthening African educational research and finding ways to address the complexities of dialects within pedagogical frameworks.