Scared of Dungeons is alliance only, some of us have horde alts but horde side is nowhere near as active as alliance I will say.
We never require voicechat for any content we do even if a lot of us use it. We mainly use it when raiding or doing 10+ keys both for social aspect and better to coordinate but its not a requirement.
It is fine to be on voice and just listen, its fine to be there and talk and its also fine to not use it at all.
if you ever feel like playing alliance again you are more than welcome to join us