Most people speak Luxembourgish, French, German and English fluent.
Luxembourg is a very good country for long distance hitchhiking. The best directions from Luxembourg are East of France, Italy, Switzerland and South of Germany. The best places are in fuel stations cause every stranger who comes from another country can buy cheap gas, alcohol and tobacco. You can do it too.
Local hitchhiking on the countryside of Luxembourg is somewhat less straightforward and hitchhiking is not so common there.