TLDR: AI interpreting startup Kotoba Technologies has successfully closed its second seed funding round, raising $11.83 million. This brings their total seed funding to $13.33 million. The capital will fuel the company’s shift from research and development to commercialization, facilitate global expansion beyond the US and Japan, and enhance its real-time AI speech technology offerings.
Tokyo- and Seattle-based Kotoba Technologies, a pioneering artificial intelligence interpreting startup, has announced the successful closure of its second seed funding round, securing an impressive $11.83 million. This latest investment elevates the company’s total seed funding to $13.33 million, building on an initial $1.5 million raised in its first seed round.
The second seed round, which officially closed on June 30, 2025, was co-led by prominent Japanese venture capital firms Globis Capital Partners and Boost Capital. Significant participation also came from SIP Capital, which had previously spearheaded Kotoba’s first seed round, alongside a diverse group of global angel investors. Notable figures among these investors include Joi Ito, co-founder of Digital Garage and former Director of MIT Media Lab, and Thomas Wolf, co-founder and CSO of Hugging Face, underscoring the industry’s confidence in Kotoba’s vision and technology.
Founded in late 2023 by Dr. Hiroyuki “Nori” Kojima (CEO) and Dr. Jungo Kasai (CTO), both former Meta employees with extensive backgrounds in AI research, Kotoba Technologies was established to address a perceived gap in the application of generative AI for non-English languages. The company specializes in developing state-of-the-art foundation models for real-time speech applications, with a particular focus on AI-powered simultaneous interpretation.
The newly acquired capital is earmarked for several strategic initiatives. A primary objective is to accelerate Kotoba’s transition from intensive research and development to full-scale commercialization. The company also plans to significantly expand its global footprint, moving beyond its current operational bases in the US and Japan. This expansion will include increasing language availability to encompass Chinese, Korean, and Spanish, broadening the reach of its innovative solutions.
Kotoba Technologies has already demonstrated its capabilities with the DOTSU iOS app, which offers speech-to-text simultaneous interpretation and has recorded over 500,000 sessions with sub-500 ms latency. Looking ahead, the company is poised for global deployments in August, featuring flagship press events that will showcase its AI-powered speech-to-speech simultaneous translation technology. A desktop application for speech-to-speech translation is also anticipated soon, alongside the rollout of highly expressive text-to-speech (TTS) models in Japanese.
While Kotoba’s primary market focus remains business-to-business (B2B), its DOTSU iOS app also caters to individual consumers. The company’s innovative work has garnered recognition, including being selected twice for Japan’s government-backed “GENIAC” generative AI project, which aims to advance speech AI infrastructure through large-scale computational resources.
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Justin Turkat, Founder and Managing Partner of SIP Capital, expressed strong support for Kotoba, stating, ‘Kotoba Technologies is trailblazing the future of voice AI, right here in Japan. We’ve backed Nori, Jungo and the team since 2023 and are excited to continue the journey.’ This sentiment highlights the ongoing commitment from investors as Kotoba continues to push the boundaries of real-time AI interpretation.
