A carefully composed, subtle, and surprising ambiguity-driven cartoon by Mick Stevens in the New Yorker 1/1&8/2024 issue (on-line on 12/2/23):
Were we expecting a baby?, conveying not ‘Were we pregnant?” but the surprising ‘Were we expecting a baby (to appear at the door, to visit us, to be delivered to us, etc.)?’ — compare Were we expecting a special-delivery letter? Were we expecting the Spanish Inquisition? (meanwhile, there’s a Page about MS cartoons on this blog)
From NOAD:
verb expect: … [c] believe that (someone or something) will arrive soon: Celia was expecting a visit.
verb phrase idiom be expecting (also be expecting a baby): informal be pregnant: his wife was expecting again.
The thing about expect is that the verb is forward-looking in its semantics, but denotes a state, not an ongoing or repeated activity. So it occurs most naturally in simple aspect, as in the example In our paranoid way, we always expect(ed) the Spanish Inquisition. The verb can occur in the progressive aspect, as in NOAD’s example Celia was expecting a visit and its present-tense counterpart Celia is expecting a visit, but then it conveys something like immediacy, not ongoing or repeated activity.
The thing about that VP pregnancy idiom is that it occurs only in the progressive aspect (✓She is expecting ‘she is pregnant’, but *She expects (in this sense); similarly, ✓She has been expecting for several months, but *She has expected for several months) — while nevertheless denoting a state, not an ongoing or repeated activity.