Wanting a more "realistic" experience in the fantastic showcases, I went into options and changed all the settings to veteran, and disabled the radio subtitles.
After I was finished, I felt like playing on my regular MP servers.

I noticed that if I typed anything in and hit enter, my text didn't appear in the chat box, however players using VOIP responded as if they could. I also became aware that VOIP users yelling at me meant that they thought I was ignored chat other players had typed, which I couldn't read.
I changed all of my game settings back to "Default" (all the non difficulty options enabled)and player text/my text still didn't appear on-screen, however I was able to type (but not read my messages thereafter).

The only manner in which I could restore chat was to delete my account and make a new one... which was a pain in the a*s seeing as I had to recreate everything in VAS and change all my difficulty settings and color settings to how I liked them.