Default Language

This mod can automatically set Minecraft to your system’s language on first launch

It is mainly used for making modpacks.

by using Mixin to hook into Minecraft’s option file loading process. When the game launches for the first time and the options.txt file has no lang: entry, the mod detects your system language, converts it to Minecraft’s language code format (e.g. zh_cn), writes it to options.txt. If the conversion fails or the language is empty, it falls back to en_us.