[technothrasher]

I've got a life long friend who's full first name is Josh, derived from the Japanese name Yosh. People often try to call him Joshua and it annoys the hell out of him.

[lovemenot]

Yosh would always be an abbreviation in Japanese. And only done for foreigners, not for other Japanese.

Yoshihiro or Yoshiyuki would likely be called Yoshi by their friends.