Breakdown of Hver er að mála vegginn?
vera
to be
hver
who / what / which (one)
að
to (infinitive marker)
veggurinn
the wall
Questions & Answers about Hver er að mála vegginn?
How does er að mála translate to "is painting"?
This sentence uses the present continuous pattern you are currently learning. It combines a form of vera (to be) + að + the infinitive verb. Here, er (is) + að mála (to paint) translates directly to "is painting".
I learned that the word for wall is veggur. Why is it vegginn here?
Two things are happening. First, Icelandic attaches "the" to the end of nouns instead of using a separate word. Second, because the wall is the object receiving the action of being painted, the word changes to its accusative form. The accusative of veggur is vegg, and adding the accusative "the" ending makes it vegginn.
If I think a group of people is painting, do I change er to the plural eru?
No, you stick with the singular er. Just like in English where we ask "Who is painting?" even if it might be a group of people, Icelandic defaults to the third-person singular verb after the question word hver (who).
Does the accent mark on mála change how it is pronounced?
Yes! In Icelandic, an accent mark creates a completely different vowel sound. While a regular a sounds like the "a" in "father", an á sounds like the "ow" in "cow".