This mod, when installed alongside The Twilight Forest, causes any attempted chat commands to error and fail, in both SP and MP. This issue only occurs with this mod and Twilight Forest, not with just Fabric Language Kotlin and Twilight Forest. It also only occurs on the FIRST world load of any game session. In order to reproduce the issue, the game must be quit and reloaded anew after loading any world once. This does not apply to multiplayer, wherein rejoining the server does not fix the issue.

Tested on Fabric version 0.14.10 and Fabric API versions 0.64.0 and 0.66.0.

The following log file is from a fresh profile with the below mods. I generated a completely new superflat creative world and upon loading attempted to type commands such as "/tp ~ ~ ~", "/weather rain", "/kill" and "/give @s Minecraft:acacia_boat" (not necessarily in that order).

latest.log

Edit: I've just encountered that this issue also causes severe server delay when any kind of map is in active use either in a player's hand or displayed on a wall. This includes regular maps and Twilight's magic map.

The conflict is likely to do with Twilight's magic map.

see my comment on the TF issue. Fixing this will fix a lot of other mods too probably.