The role of mother tongue literacy in third language learning

Abstract This paper examines the effect of mother tongue literacy on third language learning in an English/French bilingual programme in Toronto. Subjects were eighth grade students who had acquired a Heritage Language at home and who had enrolled in an English‐medium programme up to grade 4. All were literate in English on entry to the bilingual programme at grade 5. In addition, some of the students had acquired literacy skills in their Heritage Language either at home or in Heritage Language programmes at school. A particular question of interest was the impact on third language learning of Heritage Language use which includes literacy compared to Heritage Language use which does not include literacy. Results showed that literacy in the Heritage Language has a strong positive impact on learning French as a third language in the bilingual programme, whereas Heritage Language use without literacy has little effect. The positive effect on third language learning is a generalised one and is not limited to literacy‐based activities in that language. The findings are discussed in terms of Cummins’ linguistic interdependence hypothesis.