The measurement of bilingualism and its relationship to cognitive ability

The present experiments explored various measures of English and Spanish language ability and compared monolingual and bilingual subjects on tests of cognitive skill. Language ability was assessed in Experiment 1. These measures were found to be highly correlated with each other, with at least two factors needed to describe the associations among the tests in each language. In Experiment 2, subjects were given tests of cognitive skill. To be included in this study, all subjects were required to show adequate understanding of English and were divided into monolingual and bilingual groups on the basis of their Spanish abilities. Monolinguals scored higher than bilinguals on most of the measures of cognitive skill, but subsequent comparisons of the monolinguals with high and low bilingual subgroups suggested that the differences were attributable to those subjects characterized as low bilinguals.