There are 3 official national languages, French, Dutch and German .
Dutch in Flanders (north , close to Netherlands), French in Wallonia, (south, close to France), German in a small area somewhere close to Germany I guess.
Brussels is bilingual, Dutch and French. Most people also speak English and are happy to.
English is the unofficial 4th language but nearly everyone knows it. One guide said that each language doesn't understand each other so they actually use English to talk to each other!!
I have noticed though, that if there is only 3 languages used on a sign it's usually French, then Dutch, then English. No German.
Often, you can communicate a lot with no words. Body language and signing is pretty good too.Leer más