Flight from Tomorrow by H. Beam Piper

That night, Hradzka slept under a bridge across a fairly wide stream; the next morning, he followed the road until he came to a town. It was not a large place; there were perhaps four or five hundred houses and other buildings in it. Most of these were dwellings like the farmhouse where he had been staying, but some were much larger, and seemed to be places of business. One of these latter was a concrete structure with wide doors at the front; inside, he could see men working on the internal-combustion vehicles which seemed to be in almost universal use. Hradzka decided to obtain employment here.

It would be best, he decided, to continue his pretense of being a deaf-mute. He did not know whether a world-language were in use at this time or not, and even if not, the pretense of being a foreigner unable to speak the local dialect might be dangerous. So he entered the vehicle-repair shop and accosted a man in a clean shirt who seemed to be issuing instructions to the workers, going into his pantomime of the homeless mute seeking employment.