i recently had a problem where in c1 i wasnt able to chat or use commands, i was in /all and people were chatting normally so i wasnt server lagging, i rejoined and it happened again im not sure if its just me or not tho
Maybe your chat is set to an invisible setting so you cannot see it. Try going into options and chat settings and see if your chat is enabled.
You need to press the esc button then options then chat setting and see if it says enable Hope this helps
at least someone noticed that i dont see my chat messages pop up in chat, and others appear to not see it too, i think... it only really happens randomly, but i think its related to a 1.9 glitch
Save all you minecraft worlds, packs, versions and stuff. Then re-install Minecraft. That should be the easiest way to fix it.