The microphone cannot be removed from the prediction box. You can block the use of the Microphone for the extension through the Chrome browser settings.
Steps to block microphone in Chrome:
1. Click on customize and control Google Chrome in the top right hand of the browser.
2. Select settings.
3. At the bottom of the page select "advanced" .
4. Under Privacy and security select "Content settings".
5. Click on microphone.
6. Under allow you should see Co:Writer.
7. Click on the Trash can to the right of Co:Writer.
8. Go back to the Co:Writer tool.
9. Click on the guess number with the microphone.
10. A pop up message will appear.
11. Click on Block
(The microphone will be on the guess window, but it will not be usable. )