ARIA instructions in other languages

Hi All--
We have a video player that includes some aria elements, including slider.  I'd like to have the default ARIA instructions (for example, "increase or decrease using arrow keys") spoken in French for our Canadian customers.  We can do that through localization of custom instructions, but I can't figure out how to do it for the default instructions.  Any suggestions? I've tried changing the language for the video player and my Chrome browser without luck.
Any help would be appreciated...
Thanks.
Mike