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It is all about shared behaviour. If a behaviour is shared by all verbs, the tag should encompass all the verbs. That is why we use the plural. "Verb" only makes sense if the verb has a specific behaviour that other verbs don't, but in this case a more specific name should be prefered.
I think as long as they're consistent (ie. we don't have both [tag:pronoun] and [tag:pronouns]) either is fine.–None–2016-09-09T11:16:19.707
It is not consistent if a tag is using the plural, and another one is using the singular. While it makes sense to have [tag:article] because Esperanto does have just an article (i.e. what in other languages would be the definite article), it doesn't have sense to have [tag:verb] since Esperanto doesn't have a single verb.–None–2016-09-09T12:04:35.483