Yea, I'm not sure either, but it's probably Chinese as it doesn't make sense to sub in the native language...like who needs subs if you understand what is being said! Maybe someone on the forum who understands the written languages can clarify for us all.
Since I only saw kanji and no hiragana or katakana, my guess is the subs are in Chinese. I don't actually read the languages though so I could be wrong.'m