Shift happens, but when? The timing of language shift in immigrant generations

This research investigates the extent and speed with which non-English languages brought to the United States by immigrants disappear through intragenerational language shift (when individuals shift to the use of English over time) versus intergenerational language shift or "mother-tongue shift" (when children do not speak their parents' non-English mother tongue). This study is important for several reasons. The causes of language shift towards English within a generation differ from the causes of language shift across generations, and which form of shift predominates can determine whether an immigrant language has the potential to be maintained or recovered in the American context. In addition, knowing which form of shift predominates will help clarify how language shift lays the stage for, reinforces, or follows other processes of immigrant assimilation.;Using data from several major surveys, including the Current Population Survey, Pew Hispanic Center surveys, the Children of Immigrants Longitudinal Study, and the Immigrant and Intergenerational Mobility in Metropolitan Los Angeles study, I first show that estimates of the timing and extent of language shift are sensitive to the choice of measures of preference, knowledge, domains of use and the population under study. Next, I assess the amount of intragenerational language shift versus intergenerational language shift in the disappearance of immigrant languages among non-Hispanic and Hispanic Americans. These results show that both types of shift contribute to the disappearance of immigrant languages in the United States, and that both forms of language shift occur more quickly among non-Hispanics than among Hispanics. Finally, I follow age cohorts from 1979 to 2004 and observe an overall decline in the use of non-English languages in favor of the use of English, although this decline is less marked among Hispanic Americans than among others. I also investigate how preferences and use of a non-English language at one life stage change as individuals age. The results are complex. For example, some adolescents who know and prefer to use a non-English language grow to prefer and use English in early adulthood while other adolescents continue to prefer and use a non-English language into adulthood.;This study provides an antidote to the assumption in prior research that the process of language shift is entirely the outcome of mother-tongue shift, an intergenerational process. It is not a simple matter of mother-tongue shift, nor is it a process experienced in the same way by all immigrant groups. The maintenance of a non-English language across generations requires that the language be passed from parents to children, but while some children continue to use their parent's non-English mother tongue over their lifetime, other children grow to prefer and use only English.