It’s not a city/country thing, it’s a noun/adjective thing. No article is used prior to an adjective, but an article is used prior to a noun. “English” is an adjective, so you say “I am English” (with no article); “Londoner” and “Englishman” are nouns, so you say “I am a Londoner” and “I am an Englishman” (in each case with the article “a”).
By the same token, when “Danish” is used to represent someone from Denmark, it is an adjective, so you say “I am Danish” (no article), and when the noun “Dane” is used to represent someone from Denmark, you say “I am a Dane” (with the article “a”). Of course, “danish” can also be a noun, but only when it represents a pastry, so if you say “I am a danish” you are saying that you are a type of breakfast pastry.
I don’t speak German, so I don’t know for sure that the adjective “Berliner” refers to someone from Berlin while the noun “Berliner” refers strictly to a type of doughnut, but assuming that German is similar enough to English in that respect then the use of “ein” by Kennedy turned “Berliner” into a noun and thus turned Kennedy into a jelly doughnut.
I admit that my previous post was a bit vapid. Trying to think in another language for a while made me forget to point out the simple fact that “British” is an adjective while “Londoner” is a noun. My problem with your “Danish” example, then, is that “Danish” is an adjective, whereas Berliner (in English) is a noun. I should have said that in the first place.
What I don’t understand is why “Berliner” is not considered a noun in German, like it is be in English. Further, why is the word for “spiritual citizen” a noun while the word for actual citizen is an adjective? My suspicion is that Kennedy could have said either and been understood.
Maybe my whole problem is that, not being a German speaker, I confuse myself with the English meaning of the word “Berliner.”
I know a little Germain and always assumed the jelly dough nut translation was correct, but urbanlegends.about.com says that there are subtleties in the German language that foreigners don’t generally learn.
According to them “ ... if President Kennedy had said ‘Ich bin Berliner,’ he would have sounded silly because with his heavy accent he couldn’t possibly have come from Berlin. But by saying ‘Ich bin ein Berliner,’ he actually said ‘I am one with the people of Berlin.’”