I still don't know what and how to write about "tribes" like the others, so I am just going to write briefly and concisely about a tribe that I am really familiar with. The Japanese tribe. Many of you may think Japan is a monolingual state , but that's not true at all. How many languages do you think are spoken or used in Japan? Maybe 2 or 3 ? The answer is 15!! , and these are all living languages.
For those who don't believe me or wishes to know more about the living languages in Japan, check out this website. http://www.ethnologue.com/web.asp You may find it interesting.