"What subject do you teach?"
Translation:Hvad underviser du i?
Yes, kind of, the literal translation of the Danish sentence is "In what (subject) do you teach?"
The Danish looks like What do you teach?, doesn't it?
But that would be "Which subject do you teach" which is technically different.
Why both "du and "i"? Subject is singular and the you can be taken to mean either plural or singular.
It's preposition "i" not pronoun "I". I imagine that "Hvad underviser I i" would also be accepted.
I in this case means in. "What do you teach in" would be the direct translation
"Hvilket emne underviser du i?" should be accepted. It's way more accurate than "Hvad underviser du i"?