Has anyone heard of the foreign language syndrome? I heard about it today on Car Talk, where a woman had a car accident and then had a French accent. Here's another story. I just can't imagine how that could happen when the person hadn't even been to the country where the accent is from.
I've heard of it described rather more accurately as Foreign Accent Syndrome - sufferers don't suddenly learn a new language, they just speak with what sounds like a different accent. See Wikipedia.
Build a man a fire and he's warm for a day. Set a man on fire and he's warm for the rest of his life.
I'm with Victor Mair on this one. I think it's something that non-speakers of the language whose accent is in question perceive. At university I watched an ethnographic film of Pentecostals speaking in tongues (sounded like gibberish tome, and mainly used a subset of the English phonemic inventory) and handling snakes.