Whenever I travel abroad and spend time with the restless natives there, I return speaking English with their damn accent!
I guess we’re often mimic the people we’re with. There is even a theory supporting such observation.
As far as accents, my English mom said that the Welsh accent is so strong that if you spent any time with them, you would end up with their accent. When I went to Wales as a little girl, I didn't start talking like my Aunt (by marriage)--mostly because I couldn't understand a darned word she was saying.