The pluralization is awkward, the pluralized titles are silly and quite unreadable in any other language than English… that is the first thing clients throw us on the head, always.
The API is ok from my point of view as the API has more systematic value it make sense from a programing perspective, therefore acceptable, might be even desired… In that case I do not read words, I read specification.
If you hassitate about the implementation… keep the pluralization all over but make another optional attribute we can use for the admin UI and vast majority of us will be happy.