We led Rime’s seed round in April 2023. Today, we’re announcing our follow-on in their $24 million Series A, led by M13 with participation from Twilio Ventures and Corazon Capital. Morgan Blumberg, Partner at M13, will join Rime’s board.
Voice is the last interface computers are still bad at. While many voice AI companies chase generic signals of naturalness, Rime takes a linguistics-first approach. The bet is that the company defining this next interface won’t be the one with the biggest model, it will be the one that can measure what ‘good’ actually sounds like, and design toward it.
When we first met Lily Clifford in early 2023, voice synthesis was dominated by incumbents that had optimized for generic utility and startups chasing viral consumer use cases. Neither was built for what enterprise voice agents actually need: accuracy on complex medical and financial terminology, voices that reflect the full diversity of the people they’re serving, and a naturalness that holds up in real-time conversation. Lily saw that gap clearly, and she had the credentials to close it. She left her Stanford linguistics PhD to start the company alongside Co-Founder Brooke Larson (PhD linguist, ex-Amazon Alexa) and engineer Ares Geovanos (ex-UCSF brain-computer interface research). Rime blends an academic foundation with one of the world’s largest collections of expressive multilingual conversational speech, a dataset that is genuinely difficult to replicate.
Today, Rime powers nearly 100 million phone calls monthly for enterprise customers including Mayo Clinic, Dialpad, Upstart, and Asurion. The platform has gained particular traction in healthcare and financial services, where pronunciation accuracy and compliance requirements are critical. A Miravoice study evaluating 12 voices across 100,000 calls found Rime produced statistically significantly lower hang up rates and the fastest time to completion of all providers tested.
Alongside the financing, Rafael Valle joins as Chief Science Officer, bringing experience leading audio research at Meta’s Superintelligence Labs. The funds will go toward deepening Rime’s proprietary dataset and scaling engineering and research.
“The things that matter most in conversation are the hardest to pin down. There’s no unit test for sounding like you care. That’s exactly why this is a design problem, not just an engineering one. We’re building voice interaction models, systems where our linguistic judgment and taste become research instruments, not afterthoughts. With this new funding and Rafael Valle joining as Chief Science Officer, we’re 10x-ing our data investment to define the design language of conversational general intelligence.” – Lily Clifford, CEO
“Lily and the Rime team have the rare combination of linguistic expertise and engineering rigor to build something genuinely defensible here. We are proud to double down.” – John Vrionis, Unusual Ventures
Congratulations to Lily, Brooke, Ares, and the full Rime team. Onward!
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