In Luxembourg, which one of the 3 languages is most popular as the spoken language at home?

Answer 1

The national language, Lëtzebuergesch. (spelling?)

This language is closer to German than to French, and the people in Luxembourg I met used German as second language.
But I was in the northern part of the country, it might be different in the South.

Added:
Dutch is not a native language in Luxembourg, although some (few) people have learned it as second language.

Answer 2

Lëtzebuergesch, Dutch and German. There is also a part where French is spoken more than the other languages. English is also widely spoken since Luxembourg has a developed banking industry.