Different sources of delay and acceleration in early child bilingualism

The present article argues that the two effects observed in bilingual first language acquisition, delay and acceleration, have different sources. Whereas delay can be due to cross-linguistic influence on the competence or the performance level and to the mere cognitive burden to process two languages, acceleration is always rooted in efficient computation in a non-linguistic sense. The evidence for the difference between delay and acceleration effects stems from children who are raised bilingually from birth and who are studied during spontaneous speech production. It falls out rather naturally that linguistic development is immune to acceleration, while it can be delayed in bilingual children as compared to monolinguals.