Japanese is both a person of Japanese ancestry and the language of Japanese. hmm! link
Jap·a·nese (jăp'ə-nēz', -nēs')
Of or relating to Japan or its people, language, or culture.
n., pl. Japanese.
a. A native or inhabitant of Japan.
b. A person of Japanese ancestry.
2. The language of the Japanese, possibly related to the Altaic family, written in kana and Chinese characters.