In spoken English if for example: someone says “cars tires” then how to know if the speaker is talking about car’s tires or cars’ tires. Because the pronunciation is same for both.
There is no way to tell. You have to determine it from context (were we previously talking about one car or several cars?). If you are speaking and want to make it clear you could say something like "the tires of all the cars" or "the blue car's tires" (in the case where there's only one blue car we might be talking about) .