Troubleshooting Common TTS Problems

Voices and Languages Other than US English

If you are using text-to-speech languages other than US English and thus do not have any US English TTS licenses or voices installed, you must edit your client_property.conf file and change the SYNTHESIS_LANGUAGE parameter to a language you do have installed (it defaults to US English).

For instance, if you only have UK English licenses, then you would change the line to read:

SYNTHESIS_LANGUAGE = en-GB

This particularly affects MRCP users, since a new MRCP request does not specify which language to use when an MRCP session is opened (it is specified after the session is established). When starting a new MRCP session, LumenVox will open the session using the SYNTHESIS_LANGUAGE specified in the configuration file.

The most common symptom of not having a valid language set for SYNTHESIS_LANGUAGE is the following error: -55 Either no TTS servers active or none have the required capabilities.