Why doesn't my Kinect microphone recognize my voice?
No matter how loud I speak or how close I am to the device my Kinect still doesn't recognize my voice.
Xbox One Kinect. Included with the Xbox One. It has successfully sold over 23 million units around the world.
Try going through the steps on the troubleshooting page
and if that doesn't work try contacting them on their website
If all of that fails then you have the choice to attempt to repair it yourself (WARNING: This will void the warrantee and Microsoft will not take it) or send it in to Microsoft for repair which could take more than a month.