ThinnestAI × Cartesia: Accepted into the Cartesia Startups Program
Bringing Expressive Voice AI to India
We're thrilled to announce that Thinnest AI has been accepted into the Cartesia Startups program — a partnership that brings world-class voice synthesis technology to our platform and accelerates our mission of building India's most natural-sounding voice AI agents.
Cartesia is redefining what's possible in real-time speech synthesis. Their Sonic-2 model delivers emotionally expressive, ultra-low-latency TTS that sounds indistinguishable from human speech — and it's now powering voice agents on Thinnest AI.
Why Cartesia?
Voice quality is the single biggest factor in whether users trust and engage with a voice agent. Robotic, flat TTS kills conversations. We evaluated every major TTS provider and Cartesia stood out for three reasons:
1. Sonic-2: The Fastest Expressive TTS
Cartesia's Sonic-2 model achieves sub-90ms time-to-first-audio — the fastest in the industry for expressive speech. This isn't just fast monotone output; Sonic-2 generates speech with natural pauses, emphasis, and emotional range that makes conversations feel genuinely human.
For our Indian language users, this means voice agents that don't just speak Hindi or Tamil — they speak it with the right cadence, tone, and warmth that builds trust.
2. Multilingual Indian Language Support
Sonic-2 supports Hindi, Tamil, Telugu, Bengali, Marathi, Kannada, and other Indian languages with native prosody patterns. Combined with our Vega STT for Indian language recognition, this creates a fully India-native voice pipeline.
The model handles code-switching between Hindi and English naturally — matching how Indians actually speak in business contexts.
3. Emotion and Expressiveness
Unlike traditional TTS that reads text in a flat tone, Cartesia's models understand context and generate appropriate emotional responses. An empathetic customer service response sounds caring. A confirmation sounds confident. A greeting sounds warm. This emotional intelligence in voice is what separates good voice agents from great ones.
What This Means for Our Users
The Cartesia Startups program directly improves voice quality for every Thinnest AI user:
- More natural conversations: Sonic-2's expressive output makes voice agents sound human, not robotic
- Faster responses: Sub-90ms TTFA means zero perceptible delay between thinking and speaking
- Indian language quality: Native prosody for Hindi, Tamil, Telugu, Bengali, Marathi, and more
- Emotional range: Voice agents that respond with appropriate tone and feeling
- Code-switching: Natural Hinglish and regional language mixing without artifacts
Building for Bharat's Voice-First Future
India is a voice-first market. Over 500 million Indians prefer voice interactions over text, and most business communication happens in regional languages mixed with English. With Cartesia's Sonic-2 powering our TTS pipeline, we're building voice agents that truly understand and speak like Indians do.
Our roadmap with Cartesia includes:
- Custom voice cloning for enterprise brands — your agent speaks in your brand's voice
- Dialect-aware synthesis — Bhojpuri Hindi sounds different from Delhi Hindi, and our agents will reflect that
- Emotion-driven responses — agents that adapt tone based on customer sentiment in real-time
- Ultra-low-latency pipelines — combining Cartesia TTS + Vega STT for sub-500ms end-to-end voice agent responses
Try It Yourself
Experience Cartesia-powered voice agents on Thinnest AI — try our live demo in Hindi, English, or Tamil and hear the difference expressive TTS makes.
Or sign up for free and build your own voice agent in minutes:
25 free voice minutes • 200 chat messages • No credit card required
Thank You, Cartesia
We're grateful to the Cartesia team for supporting our vision of making voice AI accessible to every business in India. Their technology is helping us close the gap between how AI agents sound and how humans expect them to sound. This partnership is a major step forward.
— The Thinnest AI Team