There are a lot of achievements but they can't be translated.

They can, but it means changing
addAchievementDesc("achAlps", "Alps", "Biome Found!");
to something like
addAchievementDesc("achAlps", "achievement.bop.alps", "achievement.bop.biomefound");

And adding their appropriate localizations to the lang file.

@Adubbz I've changed it and edited lang file but it doesn't work. In game I'm getting "achievement.bop.alps" "achievement.bop.biomefound" instead of "Alps" "Biome Found!". What I need to change next?

@VERYBIGBRO Make it addAchievementDesc("achAlps", I18n.getString("achievement.bop.alps"), I18n.getString("achievement.bop.biomefound")); Remember that you need to import I18n from minecraft and not the other ones that may be in the list (there are quite a few for me).

Mkay, i can do the code part for you, however i would appreciate it if you could do the translations beforehand in the above format to save me some trouble.

Can be closed.