"I am John."
Translation:Én János vagyok.
I think "Én John vagyok" should be accepted. My name is "Pawel" (Paul in English) and I do not use the English substitute but rather my actual name when I introduce myself. So if my name's indeed John, would you really use the Hungarian name when introducing?
No, you would be called John. Maybe the purpose here is only to introduce a Hungarian name and show what its English version is.
And the Hungarian version of Pawel would be Pál. (But, of course, you would still be called Pawel.)