Try the menu method: Settings/Accessibility/Audio Guide. Make sure this setting says Off. On my Sharp TV, there's also a Shortcut setting that lets you disable the * button press to toggle the voice. Set that to disabled. That way you can't trigger it in error.
Dan Nvidia Shield, Roku Stick (3600), Ultra (4640), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.