Using HRAF's ethnographic reports from 11 immigrant groups to North America (1959-1989), the author asks: what social structural factors account for these patterns of language loss and retention? While focusing on the second and third generations, this study assesses the impact of residence, religion, school, festivals, homeland, marriage, and labor on language retention. The author suggests that residential closeness and the continued practice of religious rituals from the country of origin are the main factors influencing mother tongue maintenance into the third generation, while participation in community festivals is a marginal predictor.