Smallest.ai, officially known as Smallest Inc., announced it has closed a $13 million Series A investment led by Seligman Ventures, with participation from Sierra Ventures and 3one4 Capital, which were the main backers in its $8 million seed funding round in October. The round brings Smallest.ai’s total amount raised to date to over $21 million. The company debuted a new asynchronous speech-to-speech model called Hydra, based on its “Voice 4.0” architecture, designed to make AI conversations more natural, responsive and scalable. The startup highlights a global voice AI industry currently valued at $2.4 billion annually, which a study by Market.US expects to grow to more than $47.5 billion by the end of 2034. AI currently accounts for less than 1% of the world’s voice interactions. Founder and Chief Executive Sudarshan Kamath said existing voice AI systems struggle with latency and robotic interactions due to a chained stack of separate technologies, including speech recognition, large language model processing, orchestration layers, memory systems, text-to-speech engines and guardrails. Hydra is the foundational model at the heart of Voice 4.0, which Kamath described as a paradigm shift following earlier Voice 1.0, 2.0, and 3.0 models.