Well my intention was the proper grammar for the category. A possible alternative could be that we include the language in both English and its native spelling. For example, "Road signs in the Portuguese language - Português" Fry1989eh?21:06, 17 September 2017 (UTC)Reply
I think it's best to name categories as XYZ objects in ABC, where ABC denotes a language. Although ABC XYZ objects is more concise, it leads to confusion between country and language, e.g. French signs could be signs in France or signs written in French. In the unlikely event that a language has the same name as a country, name it XYZ objects in the ABC language. (Is there any?) ABC language XYZ objects is unnecessarily long for most languages.--Roy17 (talk) 22:34, 20 May 2019 (UTC)Reply
(I am not a native speaker.) Adverbs follow the order of "manner, place, time", so it could be Signs in French in France in the 1890s for example. But if we use modifiers, it could be 19th-century French(-language) signs in France.
I did not think of the problem of multiple adverbs in the first place. Now as I see it, I feel that <subjects> in <language> is better than <language>-language <subjects>, but <language>(-language) <subjects> in <country> is better than <subjects> in <language> in <country>. I come up with the following suggestions in order of my preference:
parent cat: <subjects> in <language>. subcats: <language> <subjects> in <country>.
parent cat: <language>-language <subjects>. subcats: <language> <subjects> in <country>.
Not all adjectives are demonyms, such as Yiddish and Urdu. Look at Category:Categories by language for examples. It's quite understandable to omit -language for these. And if we do that, we might as well omit it for all languages, because the context is clear enough such that people understand German signs/books/newspapers in France refer to stuff written in German but not maybe made in Germany or artifacts from Germany. So I'd prefer #2.--Roy17 (talk) 00:03, 10 June 2019 (UTC)Reply
I disagree. Yiddish and Urdu are logical exceptions because there is no possibility for confusion. There's no reason to extend that logic to other language adjectives that are also nationality adjectives. And there's no reason not to use the system that is both most consistent and leasy ambiguous. Themightyquill (talk) 08:49, 10 June 2019 (UTC)Reply
@Roy17: "Foo-language somethings in Someland" for picture categories. Categories of non-picture images such as screenshots, illustrations and SVG files have not fully transitioned yet. --Iketsi (talk) 12:40, 8 October 2021 (UTC)Reply
"Category:English-language SVG" to set the correct expectations for other "by language" categories, and to group them in autocompletions. --Iketsi (talk) 15:36, 12 October 2021 (UTC)Reply
I suggest to discuss this major change via COM:VP, otherwise this CFD won't be closed forever (happy for this panorama)?Support Probably a bot need to rename those categories, and edit in those categories to follow your idea. Liuxinyu970226 (talk) 04:15, 15 October 2021 (UTC)Reply