Version: randomtweaks-1.11.2-1.2.0.0.jar
Forge: forge-1.10.2-12.18.3.2234-universal

If this mod is loaded, it messes with the translations of a lot of other mods, including forge itself.

Command replies etc appear only as the placeholder string.

As seen in here: (I actually reported this issue to forge itself as I couldn't figure out at all what causes it)

MinecraftForge/MinecraftForge#3722

EDIT: This issue still exist, the fix in the above issue is for 1.11 and something different.

Fixed in 1.3.0.0. Thanks for pointing it out!