When using English and Spanish, you need to create an English and Spanish prompt files, correct? We have a customer that implemented both languages and they use SSML tags in their application. They are testing Spanish and feel they are needing to do the alot more work for Spanish translations which they claim is a very difficult task. They already modified their application for English and it working well.
Let me just add a quick note - in our testing of Spanish, which was frankly limited, it just referenced our spanish text file of prompts.