1. A system that converts text to speech, the system comprising: a response engine to generate a response text and a response intent based on user input; a non-lexical cue insertion engine to: receive the response text and the response intent representative of intended meaning to be conveyed by non-lexical cues; determine insertion points of non-lexical cues based on the received response intent; and insert a non-lexical cue at the insertion point within the response text to generate augmented text; and a speech synthesizer to synthesize speech from the augmented text using speech units associated with the response text and the inserted response intent.