Yes, you can use your own voice commands in Google Glass apps with the Mirror API. You'll just need to set up a few things first.
- Make sure you have the latest version of the Google Glass GDK and XE12 update.
- Set up the GDK and Mirror API environment following these instructions.
- Follow the instructions here to create a mirror service.
- Set up your voice commands following these instructions.
Now you should be able to use voice commands in your Google Glass apps!