What is Direct Line Speech?

Direct Line Speech is a robust, end-to-end solution for creating a flexible, extensible voice assistant. It's powered by the Bot Framework and its Direct Line Speech channel, that is optimized for voice-in, voice-out interaction with bots.

Voice assistants listen to users and take an action in response, often speaking back. They use speech to text to transcribe the user's speech, then take action on the natural language understanding of the text. This action frequently includes spoken output from the assistant generated with text to speech.

Direct Line Speech offers the highest levels of customization and sophistication for voice assistants. It's designed for conversational scenarios that are open-ended, natural, or hybrids of the two with task completion or command-and-control use. This high degree of flexibility comes with a greater complexity. Consider Custom Commands for scenarios that are scoped to well-defined tasks using natural language input.

Direct Line Speech supports these locales: ar-eg, ar-sa, ca-es, da-dk, de-de, en-au, en-ca, en-gb, en-in, en-nz, en-us, es-es, es-mx, fi-fi, fr-ca, fr-fr, gu-in, hi-in, hu-hu, it-it, ja-jp, ko-kr, mr-in, nb-no, nl-nl, pl-pl, pt-br, pt-pt, ru-ru, sv-se, ta-in, te-in, th-th, tr-tr, zh-cn, zh-hk, and zh-tw.

Getting started with Direct Line Speech

To create a voice assistant using Direct Line Speech, create a Speech resource and Azure Bot resource in the Azure portal. Then connect the bot to the Direct Line Speech channel.

Conceptual diagram of the Direct Line Speech orchestration service flow

For a complete, step-by-step guide on creating a simple voice assistant using Direct Line Speech, see the tutorial for speech-enabling your bot with the Speech SDK and the Direct Line Speech channel.

We also offer quickstarts designed to have you running code and learning the APIs quickly. This table includes a list of voice assistant quickstarts organized by language and platform.

Quickstart Platform API reference
C#, UWP Windows Browse
Java Windows, macOS, Linux Browse
Java Android Browse

Sample code

Sample code for creating a voice assistant is available on GitHub. These samples cover the client application for connecting to your assistant in several popular programming languages.


Voice assistants built using Speech service can use the full range of customization options available for speech to text, text to speech, and custom keyword selection.


Customization options vary by language/locale (see Supported languages).

Direct Line Speech and its associated functionality for voice assistants are an ideal supplement to the Virtual Assistant Solution and Enterprise Template. Though Direct Line Speech can work with any compatible bot, these resources provide a reusable baseline for high-quality conversational experiences and common supporting skills and models to get started quickly.

Reference docs

Next steps