In our Office Hour ‘Voicebots & Teneo’ we have seen an introduction to the topic, two possible implementation approaches in Teneo and started a discussion about its pros and cons.
Hi Tom! Based on previous experiences, I would recommend the Microsoft Speech Services as it offers high quality for STT & TTS, and can be customized very easily if required (e.g. fine tuning the speech model or creating your own neural voice with the right tone for your company)
You can investigate more in this documentation section. Hope this helps!