My theory: get to know three languages...
... and you can talk to just about everybody in Europe, not necessarily fluently but enough to communicate. Learn one language from each of the three big branches of the Indo-European family: Germanic (such as this, now the world’s second language), Romance and Slav(on)ic.

P.S. Corrections: to agree with the formal you in ‘Удачи вам!’ (where the you should be capitalised: Вам — otherwise it’s a plural) the verb in ‘Учись русский язык, конечно!’ should change to Учитесь. Простите меня!