This article synthesizes existing and presents new comparative data on the shift from immigrant languages to English, with a focus on the American Upper Midwest. The communities under discussion include German, Norwegian, Finnish, Walloon, and others. All had non-English monolinguals according to 1910 US Census data, and while communities differed considerably in how fast their members acquired English, all continued to have bilingual heritage speakers until roughly the same time, with the youngest generally born in the 1940s. Among other things, at least for Wisconsin, this timing correlates tightly with consolidation of state control of what had been locally run schools. These findings provide a new kind of support for the verticalization model of language shift.