Here is a list of all 15 languages spoken in Japan:
1. Ainu
2. Amami-Oshima, Northern
3. Amami-Oshima, Southern
4. Japanese
5. Japanese Sign Language
6. Kikai
7. Korean
8. Kunigami
9. Miyako
10. Okinawan, Central
11. Oki-No-Erabu
12. Toku-No-Shima
13. Yaeyama
14. Yonaguni
15. Yoron
Read more: http://wiki.answers.com/Q/What_languages_are_spoken_in_Japan#ixzz2Z9UuZLwZ