"The tram" vs "A restaurant"

[Tom]

[Jamie (K)]

I think it's because streetcars (aka "trams") are generally interchangeable objects, and people don't distinguish among them, especially because they are part of a fixed transportation system. You're at a streetcar stop, the streetcar comes, and you get on it. As long as it's got the right number, you don't pay attention to which particular streetcar it is physically.

Note that we usually say people do something in "the car", and not "a car". It's assumed that the person has only one car -- or at least not a big choice of cars -- and that people don't care which one is being talked about. If we said, "You can learn language in a car," it would sound as if we were saying, "Go choose any car -- even someone else's -- get in it, and learn a language there."

Restaurants, on the other hand, are usually more distinctive, and people select them more carefully. This is why you get "a" with this one.

That's my theory, anyway.