Hi Michele,
to obtain this result you should create a custom component and implement the desired functions.
I cannot suggest you a specific system because it depends on your requirements but you should refer to java based tools. Anyway you can find all needed informations on internet (e.g. http://freetts.sourceforge.net/docs/index.php and https://github.com/lkuza2/java-speech-api).
To create a custom component refer to these guides:
WebRatio 7 https://my.webratio.com/learn/learningobject/custom-unit-guide
WebRatio 8 Mobile https://my.webratio.com/learn/learningobject/custom-components-back-end-v-80 and https://my.webratio.com/learn/learningobject/mobile-custom-components-v-80