They sure as hell did. .....
Nope. Some few anomalous cases aside, the fairy tale of "you shall not speak Italian in this house!" from parents who spoke only Italian themselves (for example) did not - of course - happen. The inevitable success of the children or second generation in acquiring English became, over time, part of a family myth clung to by generations far removed. Young children who came here/come here eventually and inevitably learned English. The parents, depending on their age, circumstances, and prior education will eventually acquire English to an extent, but not often full fluency. If the family arrives with grandparents, they usually say "screw it" and rely on their grandchildren for interpretation. By a second generation, fluency is almost always achieved (then as now), and by the third most speak English only at home as a matter of course.