I am one.... i have realised this recently.. actually not recently, but a couple of years ago.. i tend to talk like the people i spend time with... in time, i get their twangs, their tone etc etc... when i speak with them i.e....
I remember in bombay, there were a couple of colleagues i would spend time with.. at times, i would use their catch words.. or talk in their sing song voice!!!! I dont know why... it just happens i guess!!!
The weird part is... this does not happen when talking to foreigners.. my accent does not change.. if anything i speak faster!!!! lol
So now here at my work place, i was interacting a lot with a colleague, and she had a habit of saying "hmmm..ooook" to almost everything... after a few days i realised i was also saying hmmm oook to everything.... now i have another colleague who talks real fast... i am too doing that.. unconsciously... the minute i realise it, i catch myself and try to speak slower... not slower but basically the way i do!!!!
Its very strange.. i wonder if people get offended or something!!!! :)