These strings come from Cite, not VE :)

@Esanders did this change recently I think?

"Label text for the toolbar items under the 'Insert' (other) group if VisualEditor is configured that way.\n\nParameters:\n* $1 – citation type label\n {{msg-mw|cite-ve-dialogbutton-reference-tooltip}}\n {{msg-mw|cite-ve-dialog-reference-useexisting-tool}})\n{{Identical|Reference}}",

Is it the problem that it's "Reuse reference" and "Basic reference", in English, but

But it'd be "$1 reference" and "reference $1" in any other language where the adj follows the noun.

Yeah these should definitely be separated out.

The good news this only affects wikis with wgCiteVisualEditorOtherGroup = true, which as far as I can tell is only the case on mediawiki.org and not in any other wiki, including none of the Wikipedias.

Furthermore,
in Basic reference, reference is nominative.
in Reuse reference, reference is accusative.
https://en.wikipedia.org/wiki/Declension explains the grammatical concept.
Splitting sentences is never a good idea.

It's possible we can get rid of these messages entirely. It seems to be down to a config wgCiteVisualEditorOtherGroup = true, which I don't understand why we have at all. It might be a legacy thing we can get rid of?

In T223349#5184163, @Mvolz wrote:

It's possible we can get rid of these messages entirely. It seems to be down to a config wgCiteVisualEditorOtherGroup = true, which I don't understand why we have at all. It might be a legacy thing we can get rid of?

It is apparently enabled everywhere except Wikipedia, Wikibooks and Wikiversity: https://github.com/wikimedia/operations-mediawiki-config/blob/master/wmf-config/InitialiseSettings.php#L16359 and I am guessing it's means to be used on wikis where references are not as commonly used.

Some history digging reveals it was originally made for Wikivoyage: T133725

So this is actually even more complicated than the qqq documentation says, this message can actually be used with all of the different citation types:

This is of course absolutely entirely untranslateable.

So there are two possible solutions:

1. The lazy one: Change the "cite-ve-othergroup-item" message to something less grammatically abhorrent, such as "Citation: $1" or "$1 (citation)".
2. The proper one: Add a separate message for each of the possible 6 options when it's used in the "Insert" menu rather than the "Cite" menu.

In T223349#5191561, @matmarex wrote:

So there are two possible solutions:

1. The lazy one: Change the "cite-ve-othergroup-item" message to something less grammatically abhorrent, such as "Citation: $1" or "$1 (citation)".
2. The proper one: Add a separate message for each of the possible 6 options when it's used in the "Insert" menu rather than the "Cite" menu.

So this means that if there are 5 different template types registered they ALL appear in the drop-down?

I feel like for wikis where this is enabled the whole point is that they don't use references that much... and as long as you have the basic reference dialog, you don't strictly need them in the drop down, anyway, you can just go to the reference dialog and then insert template as needed. Massively cluttering the insert drop down is no good, if people want those templates easily accessible then it should be configured the other way.

I propose instead of "$1 reference", for accessing the basic reference dialog, the message just becomes "Reference," make "Reuse reference" a separate message, and then ignore any other registered templates as being for wikis configured in the other way.

This came up again at https://www.mediawiki.org/wiki/Topic:Wyic4cjwiypesdxp