[Sxr] [Xnb] Translation of MediaWiki interface is not supported by translatewiki.net
These two related Tsouic languages (originating from a small central area in Taiwan) have their portals (Portal:Sxr, and Portal:Xnb), created since long in 2017, which you can subscribe as a translator. They also indicate already their Incubator wikis.
They are still disabled as there's no support for now in the Translator tools and statistics. Languages are enabled for translation when there's a demand and a convincing desire to start translating them (probably starting by the Mediawiki interface). However, even if this is still not enabled, you can work on these incubators and develop there some pags of terminology that you may want to discuss, and that may be needed to start translting the Mediawiki UI on this site.
This suppoort page is to demonstrate you commiment to this project and ask these to be enabled (but note that if there's no progress or there are signs that you don't work actively with Wikimedia to support the import on the Incubator wiki or on a test wiki, this could be disabled by the Translatewiki.net admins until there are more contributors taking the project seriously, notably because generating the exports from Translate.wiki.net has a cost that should find a usage on an actual wiki (Wikimedia Incubator is supported but you also need an agreement with other users of its local community to monitor the initial progress and ask for a reasonable review)
Another thing you msut discuss is some additional support in Incubator itself and in the Wikiemdia multinigual tools. Now if the Incubator goes well to the creation of a new Wikipedia, of course these languages should be enabled because the support for these languages will be demonstrated. Note that Wikimedia wikis are not the only projects that you could be working on. For example you may want to translate OpenStreetMap tools, or communication tools that are hosted on this wiki, or would like to develop a wiki for any topic outside Wikimedia, that would benefit as well of the translation of the MediaWiki UI.
You made the appropriate step here. Hope your arguments will be enough to convince an adminsitrator of Translatewiki.net for you (I cannot do that myself).