One of the mentioned ways to set the LANG environment variable is described on https://www.geany.org/Documentation/FAQ#QQuestions11.
Not sure about the RTL issue. The mentioned bug in Gimp doesn't apply to Geany I think. You could try setting the `LANG`, `LC_ALL` and `LANGUAGE` environment variables, ideally one of them also affects the RTL settings. -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://github.com/geany/geany/issues/1757#issuecomment-362536232