There was a product announced a few years back called Hushme that proposed to accomplish this goal. It attempted to create an acoustic seal around the wearer's

There was a product announced a few years back called Hushme that proposed to accomplish this goal. It attempted to create an acoustic seal around the wearer's mouth, and somewhat predictably, it looked ridiculous: https://www.news.com.au/technology/gadgets/wearables/this-cant-be-the-price-to-pay-for-phone-privacy-in-public/news-story/a54e49eb556eb7bf3a58d669aec9c1eb https://www.news.com.au/technology/gadgets/wearables/this-ca...