My mother-in-law thinks I have a southern accent.
Now, I may in fact have a trace of one (shuddup, Kreekie--I know you're reading this), but not nearly as pronounced as the one I unconsciously adopt whenever I'm talking to my MIL. I can't help it--it's like it's contagious and I have no immunity.
I was raised in Texas, the product of a Missouri-born dad and a Swedish mom. A military brat surrounded by so many variations in dialect I instinctively sought neutrality of voice. Which, it turns out, made me the perfect vocal canvass for other accents to paint upon.
Same thing happened to me when the theater god and I spent a few weeks in Ireland. After two days, I was lilting with the best of them, and not intentionally. TG laughed and mocked, but to no avail. My brain just seemed to think it was the thing to do.
My daughter tells me this is a common linguistic phenomenon, especially apparent in people who seek to make those with whom they are talking more comfortable. Some sort of mirroring behavior, designed by Mother Nature to help you fit in to new situations. I can buy that. I do want the people I speak with to feel at ease.
(Mostly. Sometimes I want just the opposite, like the time I was having a small conversation with my ex-sister-in-law about her treatment of my baby brother before their divorce. I can guarantee you, there was no trace of the Midwest in my voice then. In fact, after overhearing one particular phone conversation, my kids told me I just sounded "scary," even though I never raised my voice OR made any actual threats of physical violence. But perhaps she inferred...)
Anyway, this is just a round-about way of saying we are different things to different people. I am different as a daughter than I am as a mother. In fact, a different mother to my daughter than I am to my son. The me who is a wife and life-partner is not the same as the me who is a buddy or a writing pal.
So, what's the point of all this self-analysis? Well, for me it serves as a reminder that the same thing goes for my characters. They are different people to their various friends and relations, too. My mc slides (or sometimes fights sliding) into certain patterns of behavior with family members and old acquaintances. Teasing, combative, immature, thoughtful, funny, kind, brave, whiny, relaxed...she can be any or all of these, depending on the character(s) she's sharing the page with in any given scene.
And now I'm off to open the WIP and see which of her various selves I'm dealing with today.