This Senior Language Engineer seat owns the full data stack for Retell's voice AI agents—spanning data creation, scraping, synthesis, annotation workforce management, cleaning, processing, evaluation, and analysis. The mandate: deliver high-quality datasets (text and audio) that drive modeling innovation and make Retell's AI sound natural, humanlike, and aligned with real customer expectations.
You will define requirements and engineer web-scale pipelines, manage annotation teams (guidelines, QA, quality targets), and apply sharp linguistic judgment to produce preference data. The role partners closely with researchers, ML engineers, and product managers, bridging research and production to ensure the next generation of voice agents are best-in-class. Reports into the engineering org, with high autonomy and direct impact on core product and modeling outcomes.