Learning a second language makes your first one stop feeling normal. That’s half the fun.

Your first language feels like a transparent window rather than a set of choices, because you never had to pick any of it. Learning another one reveals that your tenses, word order and expressions were one option among many, and suddenly you can see the glass. Odd features of your own speech become visible for the first time, and that strangeness is one of the real pleasures of the work.

Notice one thing your language does that the new one does not. Ask somebody learning your language what they find hardest about it, and listen to the whole answer.