Could this be Anthony Boucher's [The] Barrier?

The first difficulty was with language.
That is only to be expected when you jump five hundred years; but it is nonetheless perplexing to have your first casual query of: “What city is this?” answered by the sentence: “Stappers will get you. Or be you Slanduch?”
It was significant that the first word John Brent heard in the State was “Stappers.” But Brent could not know that then. It was only some hours later and fifty years earlier that he learned the details of the Stapper system. At the moment all that concerned him was food and plausibility.

I can't see any mention of "ceepies" though.

Could this be Anthony Boucher's [The] Barrier?

The first difficulty was with language.
That is only to be expected when you jump five hundred years; but it is nonetheless perplexing to have your first casual query of: “What city is this?” answered by the sentence: “Stappers will get you. Or be you Slanduch?”
It was significant that the first word John Brent heard in the State was “Stappers.” But Brent could not know that then. It was only some hours later and fifty years earlier that he learned the details of the Stapper system. At the moment all that concerned him was food and plausibility.

I can't see any mention of "ceepies" though.

Anthony Boucher's [The] Barrier.

The first difficulty was with language.
That is only to be expected when you jump five hundred years; but it is nonetheless perplexing to have your first casual query of: “What city is this?” answered by the sentence: “Stappers will get you. Or be you Slanduch?”
It was significant that the first word John Brent heard in the State was “Stappers.” But Brent could not know that then. It was only some hours later and fifty years earlier that he learned the details of the Stapper system. At the moment all that concerned him was food and plausibility.

Could this be Anthony Boucher's [The] Barrier?

The first difficulty was with language.
That is only to be expected when you jump five hundred years; but it is nonetheless perplexing to have your first casual query of: “What city is this?” answered by the sentence: “Stappers will get you. Or be you Slanduch?”
It was significant that the first word John Brent heard in the State was “Stappers.” But Brent could not know that then. It was only some hours later and fifty years earlier that he learned the details of the Stapper system. At the moment all that concerned him was food and plausibility.

I can't see any mention of "ceepies" though.