Research among groups of immigrants to the United States and Canada has iso
lated a number of possible factors for both loss and persistence of the mot
her tongue in subsequent generations. These include practice of the religio
n of the homeland, residential concentration, within-group marriage, occupa
tional specialization, visits to the homeland, and others. The research rep
orted in this article is based on data in the Human Relations Area Files fr
om I I immigrant groups to North America. The research suggests that reside
ntial pattern and religious practice are the principal factors accounting f
or mother tongue maintenance into the third generation. Appeal is made to t
he childhood language socialization paradigm in explaining this finding.