I had the whole "learned English with my parents foreign accent" thing and I was sent by my school to a speech therapist to "lose it". Kinda sad about it in a way, but it is what it is. But I watched lots of television and interacted with lots of other English speakers from various backgrounds, it definitely wasn't an isolation thing lol. Sometimes it just happens. It also happened to a friend of mine, he still speaks English with a heavy accent to this day.