Yep, November is all about punching out words without any heed for fixing plot holes or badly paced scenes or rambling, clunky dialogue. It's so you can let your imagination run free without trying to edit as you go, which totally breaks up the flow of writing. I'm a believer that you should write first, and edit later, preferably after you've got the -whole- first draft done.
On NaNo planning, I've managed to get a little summary of each chapter in the novel and update my synopsis to be a bit more fleshed out. Next up is fixing all these characters I barely have names or personalities for, one of the big bad's in the story is called "Bluemage" lol.
Afaik you can write in any language you want. Nano is a personal contest, no one is going to check your novel to see if you've followed the rules etc. There's some standard things like writing 50k in november, and that it has to be one work and not many short stories, but there's always the non-traditional nano group..
. I forget what it's called though. NaNo Rebels. They have their own forum category too.