Screen reader and alt txt

Hello GiovanniFinotto​ 

So, as far as I know, SL does not detect whether a screen reader is being used, or even whether keyboard navigation (using the Tab keys) is being used. But the Articulate staff will be better placed to answer that question. 
BUT, according to one of the essential principles for making a module fully accessible, the learner must be able to control the controls of an audible media (audio/video) in all cases: it is not only visually impaired people who use a screen reader! Therefore, your media should not start automatically at the beginning of the timeline, but rather through an action by the learner. You can set this in Video Tools/Options/Play video: on trigger. The button that triggers media playback will have clear and precise alt text explaining its function and what happens when clicked. And it will be placed (in my opinion) in second position in the focus order. First the description of the image/context, then the media playback button.

*** Of course, this can be very annoying for learners who do not use a screen reader (having to click each time to play media that would be more engaging if it started automatically). In my most recent project, I asked learners on the first screen if they use a screen reader. If so, a T/F variable is set to TRUE and each media item on each screen is stopped at the beginning of the timeline because the variable is TRUE. The learner must click the “Play” button. If the variable remains FALSE, the media items play automatically. Would this solve your problem? Let us know. Perhaps someone else has a better solution.