I'm losing mine. I rarely have the opportunity to speak it, other than with my parents, and they are finding that, after living in the UK for 60 years, they slip back into English rather like the way they used to slip back into our mother-tongue when we were children.
And my dc just understand a few words here and there. Greetings, words of affection, some foods.
It feels such a loss. Weirdly, I think I feel sadder about it than my parents do.