how to turn off robot voice?

I'm not sure how but something has been turned on that gives me an announcement (in a stephen hawking style robotic voice) for every single command that i use.
i can't figure out how it started or more crucially how to disable it. can anybody help?

Check the settings in System Preferences => Universal Access. It's probably "Voice Over". You can toggle it on/off with Command-Fn-F5.

thanks man, that was it. much appreciated