Learn Swedish: Vem är kvinnan som regisserar filmen? - Who is the woman who is directing the film?

Even though the sentence starts with the question word Vem (Who), you can't use it again to connect the sentence parts. Vem is strictly used for asking questions. When you use "who", "which", or "that" to describe a noun (like the woman), you must use the relative pronoun som.

In the phrase som regisserar filmen, what is the subject?

The word som is the subject! It stands in for kvinnan (the woman) to avoid repeating it. Because som is acting as the subject of this clause, the verb regisserar comes directly after it.

The English translation says "is directing", so why isn't there a word for "is" before regisserar?

Swedish doesn't have an "is doing" (continuous) tense. The single present-tense verb regisserar translates to both "directs" and "is directing". Adding är (is) before it, like som är regisserar, would be grammatically incorrect in Swedish.

As a quick refresher, why do the words kvinnan and filmen end like that?