You can find the original mod (DDLC: MAS) here: https://github.com/Monika-After-Story/MonikaModDev.
This submod create a setting option for change language, in submod category, with every language translation avalaible found in game\tl folder.
- Download here: https://github.com/Quarior/ddlc-mas-switch_tl/raw/main/DDLC-MAS-switch_tl.zip
- Place the folder from the zip in game\submods.
- Open the game.
- Restart the game for refresh.
- Done.
If you are a translator, edit the tl.txt in game\tl\language (example: game\tl\french) where translation is the language in original language (example: "French" is "Français" in French), and text_font is the text font to use in the menu screen. By default, it is "DejaVuSans.ttf".