Update speech-synthesis-markup.md

Author: sally-baolian

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

@@ -390,8 +390,8 @@ Use the `mstts:silence` element to insert pauses before or after text, or betwee
 
 | Attribute | Description | Required or optional |
 | ---------- | ---------- | -------------------- |
-| `type` | Specifies where and how to add silence. The following silence types are supported:<br/><ul><li>`Leading` – Additional silence at the beginning of the text. The value that you set is added to the natural silence before the start of text.</li><li>`Leading-exact` – Silence at the beginning of the text. The value is an absolute silence length.</li><li>`Tailing` – Additional silence at the end of text. The value that you set is added to the natural silence after the last word.</li><li>`Tailing-exact` – Silence at the end of the text. The value is an absolute silence length.</li><li>`Sentenceboundary` – Additional silence between adjacent sentences. The actual silence length for this type includes the silence after the last word in the previous sentence, the value you set for this type, and the silence before the starting word in the next sentence.</li><li>`Sentenceboundary-exact` – Silence between adjacent sentences. The value is an absolute silence length.</li></ul><br/>An absolute silence type (with the `-exact` suffix) replaces any otherwise natural leading or trailing silence. Absolute silence types take precedence over the corresponding non-absolute type. For example, if you set both `Leading` and `Leading-exact` types, the `Leading-exact` type will take effect.| Required |
-| `Value`   | Specifies the absolute duration of a pause in seconds or milliseconds. This value should be set less than 5,000 ms. Examples of valid values are `2s` and `500ms`.| Required |
+| `type` | Specifies where and how to add silence. The following silence types are supported:<br/><ul><li>`Leading` – Additional silence at the beginning of the text. The value that you set is added to the natural silence before the start of text.</li><li>`Leading-exact` – Silence at the beginning of the text. The value is an absolute silence length.</li><li>`Tailing` – Additional silence at the end of text. The value that you set is added to the natural silence after the last word.</li><li>`Tailing-exact` – Silence at the end of the text. The value is an absolute silence length.</li><li>`Sentenceboundary` – Additional silence between adjacent sentences. The actual silence length for this type includes the natural silence after the last word in the previous sentence, the value you set for this type, and the natural silence before the starting word in the next sentence.</li><li>`Sentenceboundary-exact` – Silence between adjacent sentences. The value is an absolute silence length.</li></ul><br/>An absolute silence type (with the `-exact` suffix) replaces any otherwise natural leading or trailing silence. Absolute silence types take precedence over the corresponding non-absolute type. For example, if you set both `Leading` and `Leading-exact` types, the `Leading-exact` type will take effect.| Required |
+| `Value`   | Specifies the duration of a pause in seconds or milliseconds. This value should be set less than 5,000 ms. Examples of valid values are `2s` and `500ms`.| Required |
 
 **Example**