Update what-is-text-to-speech-avatar.md

Author: sally-baolian

articles/ai-services/speech-service/text-to-speech-avatar/what-is-text-to-speech-avatar.md

@@ -30,6 +30,7 @@ Azure AI text to speech avatar feature capabilities include:
 - The voice of the avatar is generated by Azure AI text to speech. For more information, see [Avatar voice and language](#avatar-voice-and-language).
 - Synthesizes text to speech avatar video asynchronously with the [batch synthesis API](./batch-synthesis-avatar.md) or in [real-time](./real-time-synthesis-avatar.md).
 - Provides a [content creation tool](https://speech.microsoft.com/portal/talkingavatar) in Speech Studio for creating video content without coding.
+- Enables real-time avatar conversations through the [live chat avatar tool](https://speech.microsoft.com/portal/livechat) in Speech Studio.
 
 With text to speech avatar's advanced neural network models, the feature empowers you to deliver lifelike and high-quality synthetic talking avatar videos for various applications while adhering to responsible AI practices.