I am a French Engineer (so, although I haven't been back to my country for a while, it's still handy) and the French educational system will make sure you study at least 2 more foreign languages plus Greek or Latin optionally.

11 years of German -> never used it, German speak good English

7 years of English -> use it every day

5 years of Japanese -> ended up working between Europe and Japan for years

2 years of Latin -> I liked it for a while but really can't see the added value except teach you a bit of history and high strict grammar rules

Today Mandarin might be a better choice but getting a decent level of Japanese doesn't sound like a bad idea to me.

My Canadian-Vietnamese friend married a Japanese woman, his 2 kids are already speaking English, Vietnamese, French and Japanese at home. They're currently taking Mandarin lessons. They're 6 and 8. The next generation will be scary smart with languages!

J.