The purpose of this study was to determine if variation in amount of native language (L1) use influences second language (L2) production accuracy. Native English-speaking listeners auditorily evaluated short English sentences that had been spoken by a group of native English monolinguals and by the subjects in two native Italian (NI) groups. The subjects in the NI groups were matched according to their age of immigration to Canada from Italy (5.9 vs. 5.6 years), but differed according to self-reported use of Italian (36% vs. 3%). The subjects in both NI groups were found to speak English with detectable foreign accents even though they began learning English as children and had spoken English for 34 years on average. The NI subjects who spoke Italian relatively often had significantly stronger foreign accents than those who seldom spoke Italian. These findings challenge the view that ultimate success in pronouncing an L2 is determined solely by an individual's state of neurological development at the time of first exposure to the L2. It appears that the degree of activation of the L1 or the strength of its representations may also influence L2 production accuracy. © 1997 Academic Press Limited.