Opera Voice

I installed and enable it thinking it was a text-to-speech reading feature, but now that I know it's not. How do I uninstall and disable?

.... what?
it is text to speech, select text then right click and speak.

Without a Microphone

You can of course use Opera with Voice even if you do not have or do not want to use a microphone, but you will not be able to give Opera spoken commands. Instead of pronouncing the "speak" command, right-click the selected text and select it from the menu, or use the keyboard shortcut V.

Cancel a running voice prompt by pressing Esc.

from: http://www.opera.com/browser/tutorials/voice/using/