Update text-to-speech.md

Author: sally-baolian

articles/cognitive-services/Speech-Service/text-to-speech.md

@@ -94,6 +94,15 @@ For detailed information, see [Speech service pricing](https://azure.microsoft.c
 > [!IMPORTANT]
 > Each Chinese character is counted as two characters for billing, including kanji used in Japanese, hanja used in Korean, or hanzi used in other languages.  
 
+### How to calculate Custom Neural Voice training and hosting time
+
+Custom Neural Voice training and hosting are both charged by the hour. For the billing unit price, see [Speech service pricing](https://azure.microsoft.com/pricing/details/cognitive-services/speech-services/).
+
+Custom Neural Voice (CNV) training is measured by ‘compute hour’ (a unit of measure of time). Typically, when training a voice model, two computing tasks are running in parallel. So, the calculated compute hours will take longer than the actual training time. It takes less than one compute hour to train a CNV Lite voice; for CNV Pro, it takes 20 to 40 compute hours to train a single-style voice, and around 90 compute hours to train a multi-style voice. 
+
+Custom Neural Voice (CNV) endpoint hosting is measured by the actual time (hour). We will calculate the previous day's usage (hours) for each endpoint at 00:00 UTC each day. If the endpoint has been created for more than 24 hours without suspension the previous day, it will be billed for 24 hours at 00:00 UTC. If the endpoint was newly created or resumed within the previous day, it will be billed for the time since it was created or resumed until 00:00 UTC. If the endpoint is not currently hosted, it will not be billed. In addition to the daily calculation at 00:00 UTC each day, the billing is also triggered immediately when an endpoint is deleted or suspended. For example, for an endpoint created at 08:00 UTC on December 1, the hosting hour will be calculated to 16 hours at 00:00 UTC on December 2 and 24 hours at 00:00 UTC on December 3. If the user suspends hosting the endpoint at 16:00 UTC on December 3, the duration (16 hours) from 00:00 to 16:00 UTC on December 3 will be calculated for billing.
+
+
 ## Reference docs
 
 * [Speech SDK](speech-sdk.md)