Lepcha is a language spoken in Sikkim, India.
There are not many people who speak it (30-50 000), but it's quite well documented.
Lepcha people have their own alphabet, are Sino-Tibetan people, and moreover believe in Yeti.
Anyone wants to learn it?
http://sites.google.com/site/soyouwantt ... gee-books3
some books on the language (mouse down to Lepcha section).