I should never ever have to be reminded of my speech difficulties when my games console can not understand my voice.
Surge1974,via XBox support forums

Relying on speech recognition excludes all players who are either physically unable to speak, physically unable to speak to an accurate enough level to be picked up by voice recognition, or cognitively unable to understand language.

To avoid exclusion, also provide controls / menu options for all voice commands.

Best practice example: Xbox One dashboard
Best practice example: Skyrim Kinect dragon shouts