### Answer
Based on the available sources, Retell AI's real-time ASR models are trained on healthcare vocabularies and deliver
word-error rates under 7% in clinical settings. [(1) ](
)
However, the sources do not explicitly state which specific transcription model Retell uses under the hood. There is a mention in a Discord thread of Deepgram being referenced in the context of transcription issues, but this is not confirmed as the official ASR provider in the documentation. [(2) ](
)
What the documentation does cover:
- Retell offers two transcription modes:
"optimize for speed" (uses latest interim results with low endpointing) and
"optimize for accuracy" (waits longer with more context, adding ~200ms latency) . [(3) ](
)
- Both modes have similar Word Error Rate (WER) , with the main difference being accuracy in capturing entities like numbers and dates—if your use case relies heavily on these, "optimize for accuracy" is recommended.
- You can also use
Boosted Keywords to add up to 100 custom keywords to improve recognition of domain-specific terms. [(4) ](
)
For the specific transcription model name/provider, I'd recommend reaching out via:
- [Contact Sales](
)
- [Retell AI GitHub](
)
Would you like a general answer about common ASR providers used in voice AI platforms?