Same here, happened around 15 minutes ago. Everything was going as usual, I was advertising a run for a dungeon when suddenly my messages don't go through anymore. I tried relogging, disabling all my addons but nothing worked. I first thought it was spamthrottle causing this but doesn't seem to be the reason. Around 10 minutes before I couldn't speak I typed the name of a gold site that kept spamming me in guild chat, I don't know if that's related, perhaps automated mute?
EDIT: 35 mins after making this post I can now type again
