Their original voice actor left the lore community and doesn't want to be associated with it anymore, so these three letters need new VAs. Z isn't here because I'm voicing him myself. Click on them to hear what they should sound like.
Credit 2 Every1, especially @PhonicLover44 for the sprites, and Mike Salcedo for Alphabet Lore and the voices (F's is just lowercase F's voice but low pitched).