If you want, you can dump your German-speaking parts on us - a seventeenth Bundesland...
Actually, I wouldn't mind. It's not that they're that valuable, and we'd probably come out at a profit with the reduced administrative costs. Especially know that they want to be their own region thingy, rather than being part of Wallonia. Doubt they're big enough for a Bundesland though.
Anyway, on the 3 languages front. You don't actually have to learn all 3 Languages. In Flanders, French is part of the curriculum, so pretty much everyone speaks it*. Depending on personal choice, people can however opt to exchange their German lessons for Spanish, or other alternatives. Sometimes you do retain a token hour of German lessons, but most people can't speak it. (German is an official language though.)
Now, from what I know of my nephew who lives across the language border, language education in Wallonia is a lot more lenient. Dutch is a separate studying direction, so a majority opts out of it in favour of English, german or other European languages. Don't know about german, or those little german districts.
*Or something that resembles it in some form or another.
I'm from Flanders. I speak fluent Dutch, obviously, and I am eh in French. No German skill whatsoever. I'm not even sure if it's an official language.
Well, Wikipedia says German is an official language there. But after a 20 seconds read through the languages part it says that about 60% of Belgians speak Dutch, and 40% speak French. Which means that German-speaking Belgians are a minority. Huh.
The german speaking part of Belgium only has 76.128 inhabitants, and measures 854 km². There's about 1800 German speaking living is surrounding areas too.
Truly, this is just some token gift we got after the first world war. The real prizes were to be found in Africa.