I left my country about 10 years ago to come to US. I talk to my parents and friends every once in a while, so my native language is sharp but that's my only interaction with it (I read, write, speak, think, dream etc in (sometimes broken) English exclusively). But a couple days ago my mom was watching TV and I overheard the conversation (by teenagers) in the show she's watching and it blew my mind how tiny tiny little things were different in their accents. I cannot put it into words exactly what was off about them, probably something to do with stress, but it was a shocking revelation. I asked her about it and she said she can't notice any difference. I asked her to switch to some other shows to see if it was idiosyncratic style of these people, but other shows had similar differences. I guess 10 years is long enough for tiny changes in languages.