Hume AI

Hume AI is the only commercially available TTS platform where you control emotional expression through natural language prompts ("say this warmly and reassuringly" or "speak with barely contained excitement") rather than SSML prosody tags. The Empathic Voice Interface (EVI) processes both words and emotional tone in real-time conversation, responding with appropriate feeling. Octave TTS — launched July 2025 — was the first commercial TTS model to accept natural language emotional instructions. Best for mental health and wellness apps, companion AI, empathic customer service, and any use case where emotional nuance in speech is the core product requirement. Pricing from $3/mo (Starter) to $500/mo (Business) plus enterprise.