Uwu Mod 1.12.2 makes every sound into a sample of TehNut saying “uwu”. Works with subtitles and probably works with all modded sounds. It also replaces the vanilla narrator with one that only says uwu (technically “ooh wu” because the narrator isn’t very good at pronouncing “uwu”, it just makes a weird clicking noise). The entire language map is replaced with one that returns “uwu” for every translation attempt.
Configuration options are available to: change the string the narrator says, multiply the pitch of the uwu sample, enable or disable uwu language.