Microsoft might introduce a new voice input method allowing its users to control a virtual assistant using silent voice commands. Microsoft seems to be the only one who thought about such a solution seeing that no other hardware or software manufacturer that I know of had this idea. The proposed silent voice input solution would allow the user to use ultra-low voice speech input in public and mobile situations, without disturbing surrounding people in quiet environments. Microsoft’s patent does not mean that Microsoft will actually implement this new type of voice command input.
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-patents-silent-voice-command-input-method/