More Languages in general
I've spoken to latvian streamers who have been told people struggle to find the channels that speak their language.
This is an accessibility issue for those who have to spend the time scrolling through the 'other' languages in an attempt to watch streams in their languages.
Simply adding more language categories would solve this issue. Twitch could ask their creators which languages they would like adding and I'm sure it would help many streamers and viewers alike.