Update speech-synthesis-markup-structure.md

Author: sally-baolian

articles/cognitive-services/Speech-Service/speech-synthesis-markup-structure.md

@@ -29,7 +29,7 @@ Here's a subset of the basic structure and syntax of an SSML document:
 ```xml
 <speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis" xmlns:mstts="https://www.w3.org/2001/mstts" xml:lang="string">
     <mstts:backgroundaudio src="string" volume="string" fadein="string" fadeout="string"/>
-    <voice name="string">
+    <voice name="string" effect="string">
         <audio src="string"/></audio>
         <bookmark mark="string"/>
         <break strength="string" time="string" />
@@ -51,6 +51,7 @@ Here's a subset of the basic structure and syntax of an SSML document:
 ```
 
 Some examples of contents that are allowed in each element are described in the following list:
+- `effect`: This element is used within the `voice` element. 
 - `audio`: The body of the `audio` element can contain plain text or SSML markup that's spoken if the audio file is unavailable or unplayable. The `audio` element can also contain text and the following elements: `audio`, `break`, `p`, `s`, `phoneme`, `prosody`, `say-as`, and `sub`.
 - `bookmark`: This element can't contain text or any other elements.
 - `break`: This element can't contain text or any other elements.