From a teen in the U.S.: My accent, despite being m Midwest American, changes to Northeast American, Scottish, English, etc. I’ve been getting comments about it for about 3 or 4 years now, and I’m starting to think that it might be worth looking into. I would say it changes randomly, and occasionally it does, but most times it changes due to my mood. It does NOT come as a result of talking to people with a different accent.
I notice it changing occasionally, otherwise it gets pointed out.
I’ve researched this, and came up with “Foreign Accent Syndrome”; however I express no other symptoms, I’ve had no brain trauma, and my accent doesn’t change to just one.
As you pointed out, in the absence of brain injury, it is unlikely that the problem is Foreign Accent Syndrome. I would have to know a lot more about you to help you figure this out. It could be as simple as that you are a natural mimic. Although you say it happens with mood changes, not with whom you are talking to, it could be that you remember accents and when you are imagining things, you shift to the appropriate accent. It could also be a way you’ve discovered to handle anxiety. Or it could be something else. I think you’ll find that a therapist would find this very interesting and would be pleased to work with you.
You didn’t indicate whether this is causing you great concern or if you are merely curious. Either way, a few sessions with a therapist might give you the information you are looking for.
I wish you well.