Mother tongue, language of schooling and bilingual digit span

The present study investigated whether language differences in digit span are due to differential levels of familiarity and practice arising from experiences associated with the mother tongue (language of the home), language of the school or to crosslinguistic differences in word length. Mother tongue and language of schooling were varied orthogonally to create four bilingual types: Finnish or Swedish mother tongue and language of schooling (FF and SS), Finnish mother tongue and Swedish language of schooling (FS) and vice versa (SF). Subjects were tested for digit reading rate and digit span with and without articulatory suppression. The results showed that constant bilinguals (FF and SS) obtained faster reading rates and larger digit spans in their dominant language, whereas compound bilinguals (FS and SF) showed no difference between the languages on either measure. Language of schooling was identified as a powerful determinant of bilingual digit span differences, but did not account for the full range of findings.