Speak, an AI-powered language learning startup, has raised $78 million in a Series C funding round led by Accel, achieving a valuation of $1 billion. The funding round also saw participation from the OpenAI Startup Fund, Khosla Ventures, and other investors. Speak, which originated from Y Combinator’s Winter 2017 batch, uses artificial intelligence to teach languages through conversational methods, aiming to transform the way people learn. This milestone cements Speak's position as one of the fastest-growing companies in consumer AI and a significant player in EdTech. Speak's Co-founder and CTO, Andrew Hsu (@adhsu), is set to discuss this achievement at an upcoming event.