Paris-based voice AI startup Gradium reopened its seed round to new investors including NVIDIA, bringing the total raised to $100 million. The company announced the milestone Thursday, marking one of the largest seed rounds in European AI history.
Gradium builds audio models that deliver voice at scale with ultra-low latency. This means AI voices that respond almost instantly, without the awkward pause that often creeps into AI agent conversations. The company targets a delay under 200 milliseconds while approaching human-like intonation and emotional expression. Its tools cover real-time text-to-speech, speech-to-text, voice translation, and models tuned for edge devices like laptops and phones.
The startup will use the cash to open an office in the San Francisco Bay Area. Gradium said the move strengthens its position at the heart of the world’s leading AI ecosystem, placing it near major players like Anthropic, Google, Meta, and OpenAI. The expansion highlights Silicon Valley’s continued pull, even as Paris grows into a major European AI hub.
Further explaining their ventures, the startup executives lined out the development path as:
Over the past months, the company has expanded its capabilities across speech generation, speech recognition, translation and developer tooling, reinforcing its position as a leading provider of real-time voice AI infrastructure. Among its latest advances, Gradium introduced a new generation of its flagship real-time Text-to-Speech model, delivering more natural speech and industry-leading pronunciation of complex enterprise content, including acronyms, email addresses, phone numbers and alphanumeric codes.
Gradium launched out of stealth in December with $70 million from investors including FirstMark Capital, Eurazeo, DST Global Partners, former Google chief Eric Schmidt, and French telecom billionaire Xavier Niel. The startup spun out of French AI lab Kyutai, also backed by Niel. Both were co-founded by researcher Neil Zeghidour, who previously worked at Google Brain, DeepMind, and Facebook.
The company faces stiff competition from voice AI rivals. ElevenLabs reached an $11 billion valuation in February, while Google offers voice through its Gemini platform. Gradium is gaining ground regardless, publishing new models almost every month against rival cycles of six to twelve. Since December, it has landed major customers including French automaker Renault. NVIDIA’s repeat backing of startups built on its hardware signals confidence in the voice AI boom.
