I was 9 when we moved to Germany. Within 3 months I was speaking German. Like a Native. People could not blieve I was American because I didn't speak with heissen Kartoffel (hot potatoes) in my mouth.

My Spanish accent is prrrrrretty good, too. (That's me rolling my Rs for you - proof, you see)

I don't speak German very well anymore, but when I do, I still don't have an accent. In a few months I'll be moving to New York State, and will very likely lose my Southern drawl.

Accents are weird. I pick them up without intending to.