when you say you took on other accents, do you mean you knowingly and consciously did it?

if you moved to different countries, it's not really surprising you conformed to cultural norms as that would be something you probably would have had to do (depending on where) to fit in but also as some things could result in fines, jail, etc. if you did not.

but if you are consciously speaking different and acting different, i don't believe it is an actual dissociative disorder. dissociative disorders have a degree of literally and physically feeling detached/disconnected from your body, the world around you, etc. and create a lot of different symptoms, but they are not something consciously chosen or done and are often a result of a lot of stress, trauma, or other things, etc. that causes the brain to basically shut down to survive.

you could be struggling with stress and anxiety in general from moving a lot and trying to figure out where you fit in now, etc.

but as i am not an expert, i would suggest seeking out help offline if you find you are not able to adjust to your surroundings and it creates difficulties in other areas of your life if it hasn't already.