How can people wake up from comas and speak different languages?

On the news the other night, they had a story of someone that woke up from a coma ... speaking fluent German. His family explained to the doctors and the reporters that he never spoke German before. I looked it up, and it's something called "xenoglossy". There are people that supposedly woke up and spoke languages that are very rare and sometimes ancient. This is just plain weird. I was going to ask it in the psychology section, but because it's so bizarre I thought that the parapsychology section would be more appropriate. How is this possible? How could you suddenly learn an entire language while in a coma? The real kicker in this story is that he only speaks German now - he completely forgot his native language! Imagine waking up from a coma and only speaking ancient Zulu. You'd have a pretty big problem!