The Japanese language school, Meguro Language Center (in Tokyo) was established in 1990 and since then has been attended by students from all over the world.

I

わたし　わたくし　ぼく　おれ watashi, watakushi, boku, ore

私　わたし　watashi (formal)
私　わたくし　watakushi (very formal, business like)
僕　ぼく　boku (generally young boys, but some adult use as a style)
俺　おれ　ore (very casual, male language)

Updated July 12, 2020