I try to talk in minecraft multiplayer, my screen freezes up, it fills up with dirt blocks, and it crashes with an error report

I try to talk in minecraft multiplayer, my screen freezes up, it fills up with dirt blocks, and it crashes with an error report

What I expected was to be able to talk, or put a command in.

It crashed

Steps to Reproduce:
1. Open Minecraft
2. Go to smp.sp-mc.org
3. Try to talk
4. Crashed