When I was visiting Tim for 6 months, it was just after I had spent 2 months living in Canada. Growing up, I spent a lot of time traveling to Canada, and so I developed a slight Canadian lilt to my voice...which REALLY came out strong when I was there for 2 months. Since I only spent 2 weeks in the US between the trips, I still talked Canadian and you can hear it in all the vlogs I sent back.
Surprisingly, when I was back for the short visit, I still softened my US accent and sounded more Canadian than American again.