Systems and processes for operating an intelligent automated assistant are provided. In accordance with one example, a method includes, at an electronic device with one or more processors and memory, receiving a natural-language speech input indicative of a request to the digital assistant; obtaining, by the digital assistant, context information; determining, by the digital assistant, a text-to-speech mode from a plurality of text-to-speech modes based on the obtained context information; and providing, by the digital assistant, an audio output with the determined text-to-speech mode, where the audio output is indicative of a speech response to the user request.