Yes, sorry, I misunderstood the problem. Did you get it working? And did holding on the spot where the microphone used to be on the keyboard help any? If not, I had some other steps to try:

Make sure the voice input key is turned on:

- Settings > Language & input > Google keyboard > Preferences > Voice input key

While in those Google keyboard settings, also make sure that "Google Voice Typing" and "Google Keyboard" are both set to the same language.

If all of that checks out, then try clearing data for Google Voice:

- Settings > Apps > Google Voice (May need to tap the three dots on the top-right and select "Show system" for this to appear > Google Voice > Clear Cache

- If that doesn't fix it, do the same, but try "Clear Data" instead of "Clear Cache" and restart afterwards.