About a year and a half ago, Karen Butler of Newport, Oregon went to have an oral surgery and was knocked out with anesthesia.

When she woke up, instead of her usual voice, she found herself talking in some kind of a modified IRISH ACCENT.

Doctors call this Foreign Accent Syndrome.  It's an extremely rare syndrome that seems to be triggered by a stroke or brain damage.  Less than 100 cases have ever been reported, but it started popping up 70 years ago.

As for Karen, she says she still gets strange reactions even after a year-and-a-half with her new accent . . . but she's gotten used to it and really doesn't mind talking like she's from Ireland.

(Huffington Post)

Here's a video from the "Today" show where you can hear Karen talk now, and in an old home movie from before she developed her accent. I don't know about the Irish thing…sounds more eastern European to me.