Breakdown of Welchen Film schauen wir heute Abend?
wir
we
heute
today
der Abend
the evening
der Film
the film
Questions & Answers about Welchen Film schauen wir heute Abend?
Why is it welchen Film and not welcher Film?
Because Film is the direct object of the sentence, so it has to be in the accusative case.
- der Film = nominative
- den Film = accusative
The question word welch- changes its ending to match the noun’s gender, number, and case. Since Film is masculine singular accusative, the correct form is welchen.
Compare:
- Welcher Film ist neu? = Which film is new?
- Film is the subject, so nominative.
- Welchen Film schauen wir? = Which film are we watching?
- Film is the object, so accusative.
What exactly is welchen?
Welchen is the accusative masculine form of welcher, which means which.
It works like a question word that also behaves a bit like an article. Its form changes depending on the noun that follows.
For example:
- welcher Film = which film
- welche Serie = which series
- welches Buch = which book
- welche Filme = which films
In your sentence, welchen matches Film because Film is masculine singular accusative.