Add a new language for dictionary extension to work

I would like my language (ISO 639-3 code vec, “Venetan”) to be added to the list of available language in Firefox, so that I can add my dictionary ( https://addons.mozilla.org/en-US/firefox/addon/dithionario-de-lengua-vèneta/?src=ss ) and see my language when I choose “Languages” from right-click on a multi-line edit box.
Now I see “vec” because I named my aff and dic so, but I’d like to see “Vèneto” (if the language of the browser is italian), or at least “Venetan” (if the language is otherwise).

Should I create a language pack for this?

For an image, see this link.

Thank you.

You’ll want to file a bug similar to https://bugzilla.mozilla.org/show_bug.cgi?id=586085.

Thank you! I’ll follow your advice.