Role description

aria-roledescription replaces the words a screen reader says for a widget’s role. A group becomes a “slide reel”, a listbox becomes a “colour swatch picker”, and the reader’s own vocabulary for that role is gone for as long as the attribute is there. Note the shape of that trade. An accessible name says which thing this is; the role says what kind of thing it is; a role description says what kind of thing it is in your words instead of the platform’s.

The attribute changes speech and nothing else. Keyboard behaviour, the accessibility tree, the mapped role, the way a braille display abbreviates that role: none of it moves, and the braille case is the sharpest illustration, because braille role abbreviations are short by necessity and a long invented phrase eats the line the content needed. The attribute is also not translated. A reader running in Spanish hears its own word for “carousel” until you override it, and then hears your English string forever, which is a regression you will not notice in your own locale.

That leaves a narrow set of good uses. The strongest is a widget whose stock role name genuinely misdescribes it to the user: an ARIA role chosen because it is the closest available mapping, not because it is what the thing is. The worst uses invent a name for a widget that already had one (“photo strip” for a listbox), or actively lie about what the control does, which is the one failure mode with no upside at all. A reader told it is standing in a video player will look for transport keys that do not exist, and will blame itself when nothing happens.

Reach for it last. The first rule of ARIA applies in spirit as well as in letter here: if the widget needs a different name to be understood, the usual reason is that it should have been built as a different widget. When you do use it, keep it to two or three words, keep it in the page’s language, and check that the word you picked describes something the reader can actually do.