Photo: Justin Sullivan / GettyThe little-known company, led by PrimeSense founder Aviad Maizels, has been working on whispered speech and advanced audio technologies for wearable devices.Apple is acquiring Israeli AI startup Q.ai, the technology giant confirmed on Thursday. The terms of the deal were not disclosed, but the purchase price is estimated at $1.5 billion. This marks Apple's second-largest acquisition ever after the $3 billion purchase of Beats in 2014.For Q.ai founder and CEO Aviad M...