This happens in all parts of the game creative, survival, and multiplayer as well as on the opening screen. The language is selected as English and happens with any English and appears like below. If Afrikkans is selected it appears normal and can see all the languages but as soon as you click on English it changes back to the nonsense pixelation. I posted a picture of my launcher if that is needed. Happens in both converted texture packs as well as default.
1. Select Afrikkans
2. Select English (US)
3. All languages and everything in Minecraft has changed.
Please ask for anything else needed.