Speak, a startup that's revolutionizing language learning by focusing on conversational skills, has announced a significant milestone: a $78 million Series C funding round that catapults its valuation to $1 billion. This investment, led by Accel, with participation from previous backers OpenAI, Khosla Ventures, and Y Combinator, is a major jump forward for the startup, which had confirmed a Series B extension of $20 million at a $500 million valuation just six months ago.

The funding round is not only a testament to Speak's progress but also reflects the huge enthusiasm around generative AI, which is a key component of Speak's platform. OpenAI, one of Speak's key investors, is not just a financial backer but also an early partner for the latest in its speech technology. This association has proven one of the commercial opportunities for GenAI, and Speak is at the forefront of it.

Speak's platform uses AI to generate audio conversations and listens to users' responses to improve their grasp of a language. The startup's primary aim for the funding will be to expand the number of target languages users can learn with Speak — and thus its customer base — starting with Spanish and French. Currently, the company focuses on people studying English, the world's most popular language for learning, and provides learning and review materials designed around courses.

Speak's CEO, Connor Zwick, co-founder of the company with Andrew Hsu (CTO), emphasized that their value proposition has been to teach people how to communicate in a language, rather than just focusing on vocabulary and grammar. The company lists eight originating languages for learning English, based on the most popular language groups among English learners to date. With over 1.5 billion people trying to learn English, Speak's total addressable market is vast, although the company doesn't disclose its active user number. As a guide, Hsu said Speak's app has been downloaded more than 10 million times, with average usage around 10-20 minutes/day, paying $20 per month, or $99 per year, typically a fraction of the price of hiring a human tutor to work on improving conversation.

Speak for Business, an enterprise tier, has over 200 customers, the company said. The platform works in a three-step process: first, users are thrown into listening and talking; second, they apply new terms or phrases through drills; and third, Speak presents the phrase in a real-world context using AI. Although the aim is to get learners speaking a new language with humans, there are no humans in the loop, with the learning experience crafted using speech recognition, natural language processing, generative AI, and more to tailor the learning to the learner.

While Speak doesn't have any integrations with standardized language learning qualifications, the company is explicitly trying not to be a test prep solution, as they believe tests are imperfect and people end up gaming them rather than focusing on actual language skills. However, Hsu hinted that this could be part of the company's plan in the long term, with the system they're building to quantify fluency and efficacy potentially leading to a true, accurate English fluency score or test.

Gamification is also not an area that Speak has explored to date, but with more staff, the company is open to introducing more consumer-driven models like this to encourage speaking. However, Zwick emphasized that they will prioritize efficacy over engagement and gamification. Ben Quazzo, a partner at Accel who led the investment round, will be joining Speak's board of directors, acknowledging Speak's exceptional growth and market potential.

This significant funding round and valuation milestone mark a major step forward for Speak, as it continues to revolutionize language learning and expand its offerings to more languages and users. With its innovative approach and AI-powered platform, Speak is poised to make a significant impact in the language learning space.