Because not all TTS engines operate the same way, TTS engine playback may differ. For example, some TTS engines only allow up to 3 KB of text, and if you submit a string that exceeds that length it may play nothing, or it may fall back to the Genesys TTS engine if it supports the current language. Engines usually have higher latency for synthesizing large TTS requests, and TTS requests with more than a couple thousand characters at a time may not be recommended. Performance can vary depending on language, dialect, and voice. 

To test a TTS engine playback, follow these steps:

1. Create a new inbound flow or open an existing one.
2. Under Starting Menu, click Main Menu.
3. In the Initial Greeting box, add a sample text that must be played back by the TTS engine.
4. Under Settings, click Supported Languages.
5. Do one of the following:
   • Add a new supported language.
   • Locate an existing supported language.
6. In the Text To Speech column for the supported language, do the following:
   1. Under Engine, select the TTS engine for the flow.
   2. Under Voice, select the voice you want to read the text to speech.
7. Save and publish the flow.
   Note: After you change a TTS voice of an existing flow, you must republish the flow for the changes to take effect.
8. In Genesys Cloud, click Calls .
9. Click Dialpad and enter the name of the inbound call flow.
10. Press Enter. The selected TTS engine and voice plays the Initial Greeting prompt.

Test string values in third-party TTS engines

It is important to test and confirm third-party TTS engine behavior. Runtime playback of TTS strings is at the third-party provider’s discretion and may not produce the same behavior as the Genesys TTS engine. One TTS engine could read 5.0 as “five point zero,” while another could read that text as “five period zero.”

Example:

Let’s review the following string:

ToAudioTTS(ToString(MakeList(1,-5, 3)))

Using the Genesys TTS engine for playback, the caller hears one, minus five, three. However, a third-party TTS engine that plays back the same string may not read the negative number and processes the expression as one, five, three.

Best practice recommends that you test third-party TTS engine playback in an Architect test flow, or in a third party provider’s test environment. For more information about configuring a TTS engine and voice for a flow’s language, see Select a TTS engine and voice for a flow.