I noticed that some of the tags are in English, for example, preposition and culture and some are in Esperanto, for example, volativo and muziko. This seems like it will produce a lot of duplicate tags, and difficulty in searching and filtering effectively. Should there be a standard for what language the tags should be in?
I'm starting to think we should rename all of the tags to Esperanto. In the Spanish, French and Portuguese StackExchanges the tags are all in their respective languages and have descriptions in that language too. There appear to be aliases for the tag names in English.
It's interesting that on those sites there are many more questions that are in the language of the site. If we rename the tags this might encourage more people to ask in Esperanto and then the site would be more accessible to people who don't have such a good command of English.
I would say that in general we should stick with using tags in English, except in the case an Esperanto word is more appropriate because it expresses a concept that is otherwise difficult to express with an English word.
Keep in mind that EL, like many other Stack Exchange sites, is an English site. Questions in Esperanto are allowed, but the site language is still English. The site is not even prepared to handle diacritics in tags, and probably also the algorithm to detect low quality questions need to be calibrated for a language different from English.
How about bilingual tag names in the style
Esperanto tag name — english tag name?
So we'd change muziko to muziko — music, etc.
For accessibility, we'd have to add both Esperanto-only and English-only synonyms, both redirecting to the bilingual tag.
Off course, we'd probably want to have diacritics support in the tags first, or we'd have to use the x- or h-notation for them which looks kinda unpolished.