This paper uses a longitudinal approach to study language transfers to French and English by individuals whose mother tongue is neither French nor English (allophones) living in the Montreal metropolitan census area. We use data collected by the Survey on the Vitality of Official-Language Minorities (SVOLM) conducted by Statistics Canada during the Fall of 2006, a few months after the census. This survey made possible the collection of retrospective information on the moment (age) and location (in Canada, outside Canada) where the adoption of French or English as the main home language took place. Language transfers are analysed for two sub-groups : allophones born in Canada and allophones who immigrated to Canada. We examine transfer rates for selected variables such as age, length of residency in Canada and historical time (period). This paper shows that time, intensity and direction of transfer vary substantially between these two sub-groups.