I have learnt another language more than once in my life, for various reasons and with different degrees of success. In school, the French classes were not followed by choice, not met by enthusiasm and only later in life acknowledged as useful. German in school felt easy because it is so similar to Dutch but I would never claim I speak it. Latin? Same thing. Learning how to translate a text is by no means the same as speaking a language. English I seemed to have just picked up. (I think it is was because I was a key-under-the-doormat-child and I watched abnormal amounts of BBC?) Spanish was a very conscious choice, and I followed evening school because I wanted to. My motivation? I wanted to read Marquez in the original language. If even the translation is mesmerizing, then the original must be enchanting. I never managed by the way. His sentences are an average of eight lines long. But hey, I live in a Spanish speaking country so I guess I am still practicing. Swahili was a necessity, there was no communication possible any other way with some Tanzanians so we adapted.
The strangest realization I had so far is that along with grammar, you learn a bit of personality too. The intonation alone, the most common words, the word order.. it all contributes to another attitude. For instance, I find it much easier to get mad in one language than in the other. Also, this is why I believe Google translate doesn’t work. One would never say “this food is quite tasty” in Spanish, much better is the tasty “que rico!” I guess you could say polyglots become a bit schizophrenic in a way.
Even worse is it when you take over an accent. A habit I am particularly guilty of. My children do it too, depending on the teachers they have they will sound more British, American or Canadian. I would, however, never do that in my mother tongue tough.. I think. Then the dirty diphthongs and palatal a’s form my very distinct personality.
People often ask me what language I dream in. Honestly, I do not know. But I count in Flemish. Almost always anyway.