Me and my friend are trying to learn It.
I heard that people in Mitaka speak their own language called Mitakish.
They speak the Western Kanto dialect of Japanese. Western Kanto dialect is pretty much identical to ":standard Japanese":, so you can learn it from any Japanese language textbook. There is a university in Mitaka with students from all over Japan and also a lot of foreign students, so you can hear many other dialects and languages in Mitaka.
Mitaka? They speak standard Japanese.
But if you go down west to Tachikawa, they have a subtle accent.
Gee I dunno perhaps ж—Ґжњ¬иЄћ
They speak TROLLanese
official Japanese as same as other people in Tokyo speak.
Having been there, as well as several areas in Japan, I can say with almost absolute certainty – Japanese.