Satvik Sinha

Speech-to-text seems like a solved problem. But when we looked at our own Mandarin practice sessions, we found something unexpected: about one in four had words in the transcript that were never spoken. A streaming model was inserting Korean, Hebrew, and Thai into Mandarin answers. We ran the same recordings through the model after the sessions, and the transcripts were almost perfect. The models that struggled with our audio also scored well on public benchmarks. To find out why, we built a replay rig and tested four models on real sessions. We switched the model we used in production, but that still didn’t explain everything. So we kept investigating. I’ll show you what we found, step by step, including the two settings that had the biggest effect on streaming transcription—and how much each one can improve results on your users’ audio.