Currently the desired language for the VideoJS media player using some inelegant Javascript, see: https://github.com/moodle/moodle/blob/master/media/player/videojs/classes/plugin.php#L397

It is partly done like this because the lang string is to large to pass in as part of a regular `$PAGE->requires->js_call_amd()` and partly because the lang strings for VideoJS were provided as javascript files (.js).

Now that videoJS has been upgraded as part of MDL-63453 the language files are now provided as JSON (.json).

This means we should be able to refactor this code to load the required lang files via ajax in the videoJS loader.