Steps to replicate the issue (include links if applicable):
See e.g. File:Paris agreement signed.webm on Commons
What happens?:
In English, the message box says:
There are currently no subtitles in $1 for this video, you can edit this page to add them.
What should have happened instead?:
$1 should have been replaced with the user language (written in the user language), as specified in the qqq text.