In Japanese companies that I've worked at, the convention is using English words for programming concepts, using Japanese words transliterated into English for business concepts except where the English word is easy and obvious, and using a pedantic level of Japanese code comments to signpost for those developers who are less confident in their English ability.

e.g.

// 教科リストを取得する。

String[] kyoukaList = getKyoukaList();

(Japanese university backend systems have two concepts of "a subject", with kyouka being a subject like math is a subject and kamoku being a subject like Algebra II is a subject.)