Reg. LLM Speech to Text

Saranya Selvaraj 25 Reputation points
2026-10-06T09:13:57.7333333+00:00

Subject: LLM Speech transcription: API access and pricing

Hello Support Team,

We are building an application that uses Azure Speech in Microsoft Foundry, and we have two questions about LLM Speech transcription:

  1. Access: Is LLM Speech transcription enabled for our Azure subscription and Speech resource, so that our application can call it through the API? If any approval, region, or resource setting is needed to enable it, please let us know.
  2. Pricing: What are the pricing and billing details for LLM Speech transcription (billing unit and rate), and how do they compare with real-time transcription?

Thank you,

saranya

Azure Speech in Foundry Tools
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Answer accepted by question author
Manish Kumar 160 Reputation points
2026-10-06T10:44:55.59+00:00

Hello @Saranya Selvaraj

I would like to first clarify that this is a user‑to‑user support forum. Moderators here are not Microsoft Support, so we don’t have backend access or the ability to perform escalations. However, we’re happy to help with troubleshooting guidance and best‑practice recommendations.

1. Access

LLM Speech needs no approval or allow-listing. The requirement is a Speech/Foundry resource in a region where LLM Speech is available (LLM Speech documentation). Those regions are currently centralindia, eastus, northeurope, southeastasia, westus and westus2 (Supported regions – LLM speech tab).

LLM Speech isn't a separate API. It's the fast transcription endpoint with enhancedMode enabled (Fast transcription API, REST API reference). To confirm your resource has access, run this test call:

bash

curl 'https://<resource>.cognitiveservices.azure.com/speechtotext/transcriptions:transcribe?api-version=2025-10-15' \
-H 'Ocp-Apim-Subscription-Key: <key>' \
-F '[email protected]' \
-F 'definition={"enhancedMode":{"enabled":true,"task":"transcribe"}}'

If the response says "Enhanced mode is currently not supported yet," your resource's region doesn't support LLM Speech.

2. Pricing

(Azure Speech pricing)

  • Billing unit: Hours of audio sent, billed in one-second increments. This is the same for real-time transcription.
  • Rate: LLM Speech shares the same price and SKU as Fast Transcription (footnote 9 on the pricing page).
  • Compared with real-time: Real-time transcription is a separate meter with its own hourly rate. Select your region on the pricing page and compare "Fast Transcription" with "Real-time Transcription." Enterprise agreement rates may differ.
  • MAI-Transcribe: Also called through the LLM Speech API, but billed under separate meters (MAI-Transcribe documentation).
  • Usage difference: LLM Speech transcribes uploaded audio files (under 5 hours and 500 MB). Real-time transcription streams live audio.

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  1. Senthil kumar 2,585 Reputation points
    2026-10-06T10:48:55.23+00:00

    Hi @Saranya Selvaraj

    1. Access to LLM Speech Transcription

    • LLM Speech is available as part of Azure Speech in Microsoft Foundry. It enhances speech recognition with a large language model, providing improved transcription quality, multilingual support, contextual understanding, translation, and prompt-based customization. To use LLM Speech:
      • You need an active Azure subscription.
      • You need a Microsoft Foundry project and an Azure Speech resource.
      • Your application can access the service through the supported REST APIs and SDKs when the resource is deployed in a supported region.
      • Current service limits include:
        • Maximum audio file size: 500 MB
        • Maximum audio length: 5 hours per file
        • Up to 600 requests per minute per Speech resource.
      If you're unable to see or invoke the LLM Speech capability, please share:
      • Speech resource region
      • Speech resource SKU (F0 or S0)
      • Any API error message or response code
      so the configuration can be verified further.

      2. Pricing and Billing

      According to the Azure Speech pricing documentation, traditional Speech-to-Text services are billed based on audio duration (per-second billing). Standard real-time transcription and fast transcription have different pricing tiers. For LLM Speech, Microsoft documentation currently provides feature availability and service limits but does not explicitly publish a separate LLM Speech pricing meter or rate on the referenced pricing and documentation pages. Therefore:
      • Standard Speech-to-Text pricing is publicly documented and billed by audio duration.
      • LLM Speech feature documentation does not currently specify a dedicated billing unit or rate.
      • If your organization requires definitive billing details for LLM Speech, we recommend checking the Azure Pricing Calculator for your subscription or opening an Azure billing support request, as pricing can vary by region and offer type.

    Thanks

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