Dear Imed
As a follow-up to what Ron has written about ways of adding audio, I'd also recommend looking at this Xerte wiki page
xerte.org.uk/wiki/doku.php?id=workingwithaudio .
I'm also attaching a PDF guide on working with audio which I developed for a course on authoring in Xerte for language teachers that I ran earlier in the year.
Finally, there is also a way to make words or phrases clickable objects, so that when a learner clicks on them some audio autoplays, without player controls displaying. Here's an example;
languagehub.uk/xerte/play.php?template_id=310#page3
This involves inserting and editing a bit of code through Source view, and is quite time-consuming to do. I will post to the Xerte Forum separately about this.
I hope this is helpful
Best wishes
Jonathan Smith
Freelance English teacher and Xerte enthusiast