Anecdotal evidence of a multilingual person living in a country desperately scrambling to transition from one language to another: I grew up in Geneva. So Fren

Anecdotal evidence of a multilingual person living in a country desperately scrambling to transition from one language to another: I grew up in Geneva. So French at school and among friends. Then my parents and I moved to Ukraine and lived there since the independence, so Russian at home and that's my mother tongue. Ukraine has been rushing to transition its population to Ukrainian for a decade or two - all with limited success. And on top of that I am as close to being a native English speaker as possible while living abroad. So what happens in an environment like that? Looks like people tend to express and think about different parts of life in different languages. When I think legal matters in my homeland, it's mostly Ukrainian. When I think about IT and computers and while lurking here or on Reddit, it's English. Daydreaming about childhood: French. When stressed: brain loses everything but English. Inner monologue: mostly Russian. So, to sum up the question: can one lose their native tongue? Answer: I have no idea.