Babel userboxes for sign languages

Hi. As a French-Wikipedia editor, I found something that could be improved in Babel userboxes but I don't know where to start to fix it.

The problem is this: while Babel supports sign languages, the displayed text is in English. For instance, if I add |fsl-1 to my Babel box on the the wp:fr, the language code is recognized but the box reads (verbatim) "This user has basic knowledge of French Sign Language.". Same for other sign languages.

I think the text should instead be in the written language most closely associated with the sign language (e.g. English for ASL/ase, French for LSF/fsl, Italian for LIS/ise, etc.), or by default in the language of the wiki instance (e.g. French on the French Wikipedia).

Can this be done?