Microsoft has filed for a new patent at the World Intellectual Property Office (WIPO) in December 2018, which describes a voice input method to silently command the virtual assistants.

The patent describes a silent voice input solution without being noticed by surroundings. Compared with conventional voice input solutions which are based on normal speech or whispering that use egressive (breathing-out) airflow while speaking, the proposed “silent” voice input method is performed by using opposite (ingressive or breathing-in) airflow while speaking. By placing the apparatus (e.g. microphone) of the apparatus very close to the user’s mouth with an small gap formed between the mouth and the apparatus，the proposed silent voice input solution can capture stable utterance signal with a very small voice leakage, and thereby allowing the user to use ultra-low volume speech input in public and mobile situations, without disturbing surrounding people. Besides of air flow direction (ingressive and egressive), all other utterance manners are same as our whispering, so that proposed method can be used without special practice.

As always, it has to be noted that the aforementioned is just a patent, and usually, not all patents see the light of day.