This might have been a short piece rather than a full-length play; I heard about it in a news story. I don't remember any details, but the idea was that instead of actually speaking content words, the actors all just used dialogue which was generic and descriptive, although conveyed plenty of emotion and nuance. E.g.,
Alice: General question?
Bob: Non-committal reply.
Alice: Subtly modified inquiry?
Bob: Suspicious Irony? Confident dismissal.
Alice: Hesitant reiteration...
Bob: Emphatic redirection!
Alice: Shrugging acceptance, faux pleasantry.
Etc. I'm having trouble finding it because any google search for relevant terms like "play using generic words" just gives me lists of theatre jargon and the like.