Nuance (now Cerence TTS) is a technology company helping people to communicate in the language of people. This claim fits very good Harpo strategy and here is the reason for the partnership: technology in service of people, adapted to the way people communicate.  

Nuance are pioneers in speech technology. Their Vocalizer Expressive is a text-to-speech solution that provides enhanced expressivity for more natural sounding speech in a variety of applications and technologies. All voices offered at harposoftware.com are of Premium High flavour where available (highest available quality).

For Nuance voices - please look here.