And in that lies the reason why almost all the quarter hour listening to foreign language stations comes from first generation immigrants. The children generally speak the "foreign" language at home, but don't learn it correctly at school.Just like a lot of things, if you don't use it daily you tend to forget how to speak/use/wear it. Couldn't call on my long dead grandparents or great-grandparents to translate for me.
Nobody in my family has spoken Gaelic for about 180 years or so (but one picked up Spanish when he defected from the American invasionary forces in Mexico... relatives still live there!).