I do this ALL THE TIME!

I've always been somewhat of a mimic, and I can "do" accents on purpose of everyone in my family. Although I have yet to do an effective strong Brooklyn accent, I can imitate my in-laws, who are from Brooklyn, for short periods of time.

When I was in London, I would involuntarily start speaking with an accent for no apparent reason. My husband kept telling me he was horrified and "knock it off!" but I had little conscious control over it. Locals didn't even look at me twice; in fact, I was asked several times which neighborhood I lived in, or what street if I were in a pub.

I think this weird ability comes from the fact that my family and I had very strong Texan accents when I was young. But at age 11 I decided I'd had enough of "farners" (that's foreigners, in Texanese) saying how "cute" my accent was. Within one month I had COMPLETELY changed my accent, and when we traveled, people were shocked to find out I was from Texas, or I was with "those rednecks," etc. Perhaps focusing on losing my accent at that tender age activated some brain area that allows for labile accents.

My new lack-of-accent is a very generic newscaster one. But when I phone my relatives from Texas, I'm speaking with a soft Texan accent within a few minutes. With my in-laws, it's a soft Brooklyn accent within minutes.

Although I think Madonna's new British accent is an affectation, I felt somewhat sorry for her that people were making fun of it. It happens to me anytime I travel.

There are brain injuries that can cause very strange accents as well. An American speaking with a British accent, for instance, or a Chinese person suddenly using another dialect. Interesting stuff!