It’s your own worst enemy
Over at Heideas, Heidi was discussing a certain interesting predicate in English, be friends with, which looks morphologically plural, but which can appear with a singular subject. More accurately, it can take one side of a symmetric relation as its external argumeny. (For symmetric situations, you can express the sides separately (I am his friend, I met him in the park), or as a collective unit (We are friends, We met in the park)).
In the comments section, Mark Liberman notes that
The process seems to be one that generalizes to other plural predicate nominals: “is colleagues with”, “is lovers with”, “is co-workers with”, etc. These seem wierd to me in a way that “is friends with” doesn’t, but they’re out there.
Regarding the first point, this is a bit of an overgeneralization. Generally the X be NP[pl] with Y construction requires the relation to be one that is social and not on a temporary basis, or not contingent upon factors external to the participants. Well, I’m not sure if that’s exactly the right generalization, but it’s meant to account for the fact that you can be friends, colleagues, partners, buds, pals, co-stars and even enemies or rivals with someone else. But you can’t be competitors or contestants with someone.
Then again, you can also be brothers, sisters, and cousins with someone, and this isn’t exactly a social relation, but it’s about as symmetric as you can get, and permanent as well. But it’s pretty clear that be friends with is the central example of this particular construction. It’s attested well back in the language, and dictionaries have an entry for it, though sometimes it is for the collocation make friends with.
“be ages with” (for readers outside Scotland, “be the same age as”) is the construction that springs to mind for me. It’s symmetric and permanent, but you can’t say “We are ages”. It would have to be “We are ages with each other”, or “I’m ages with Kim and Sandy”.
Interesting. I’d never heard of that construction.
Can you modify “ages,” like “exactly ages with” or “nearly ages with”?
That sort of modification—”about ages with”, “almost ages with” and “exactly ages with”—is fine. “Julian is just over ages with Sandy” doesn’t sound right, as doesn’t “Julian is significantly more than ages with Sandy”.