Recently, Apple published a research paper which details its methods of improving Siri by using machine learning. The voice assistant sounds more human than ever and it seems like Apple wants to close that gap as much as they can.
Apple developed machine learning which trains itself with data to help in a text-to-speech system that can separate audio and pair them together to create a more human-sounding response.
Apple said. "We evaluated hundreds of candidates before choosing the best one. Then, we recorded over 20 hours of speech and built a new TTS [text-to-speech] voice using the new deep learning based TTS technology."