Apple’s biggest acquisition ever is still its $3 billion Beats buy in 2014, but now the second biggest deal is bringing in Q.ai, a four-year-old AI audio startup. Apple did not disclose the terms, but Financial Times reports that Apple is spending $2 billion on the company. It also mentioned Q.ai patents for optical sensor technology that could be built into headphones or glasses to recognize “facial skin micro movements,” allowing for non-verbal discussions with an AI assistant, for example.

The founders of Q.ai will join Apple, including CEO Aviad Maizels, who founded PrimeSense. Apple bought that company in 2013 and repurposed its Xbox Kinect technology to power the iPhone’s FaceID setup. This time around, tech that understands whispered speech could connect to the generative AI-upgraded Siri or other Apple Intelligence features, and work with future AirPods, Vision Pro, iPhone, or Mac devices.

In a statement provided to Reuters, Apple hardware exec Johnny Srouji called Q.ai “a remarkable company that is pioneering new and creative ways to use imaging and machine learning.” Google Ventures has backed the startup, and managing partner Tom Hulme wrote in a blog post about how this could help us find out “what happens when the computer finally ‘disappears’ into our daily lives.”