I got the same problem in Matlab R2019b @ Windows 7 x64.
MWLOCALE_TRANSLATED =OFF does not work. (the old information should be erased from Q&A)
switching 環境->設定->コマンドウィンドウ->ロケール to en_US
does not effect anything.
The option was hidden in 一般...
It was written in JAPANESE! Now think about it: how can a user not familiar with Japanese switch it to English, when it is writen as "デスクトップ言語:英語" and hidden below all the other options. This is the first thing I see when starting the software, it should be on TOP, written in big red LATIN letters! And what is デスクトップ？Luckily, I know some Japanese, and it is called ユーザインターフェース(UI), so it took more than a hour searching for a solution.