Breakdown of Nágranninn stendur við gluggann til að hlera okkur.
glugginn
the window
að
to (infinitive marker)
okkur
us
standa
to stand
Questions & Answers about Nágranninn stendur við gluggann til að hlera okkur.
Since the neighbor is just standing there (no movement), why is gluggann in the accusative case rather than the dative?
While it is a good rule of thumb that prepositions of place use the dative for a stationary position and the accusative for movement, við is an exception. When við means 'by' or 'next to' a physical object, it almost always takes the accusative case. That is why we use við gluggann (accusative) and not við glugganum (dative).
How could I use the verbs from this lesson to say 'It sounds to me like the neighbor is eavesdropping on us'?
You would use the impersonal middle-voice verb heyrist. You could say Mér heyrist nágranninn vera að hlera okkur (using an infinitive phrase) or use an að clause: Mér heyrist að nágranninn sé að hlera okkur. Notice that the 'experiencer' (me) is in the dative case (mér).
Why do we need til að instead of just að before hlera?
You use til að when you want to express purpose, meaning 'in order to'. If you just used að by itself here, the sentence would feel grammatically incomplete. Til að clarifies that standing by the window is the specific action the neighbor is taking in order to eavesdrop.
We use the pronoun okkur here. Does the verb hlera take the accusative or the dative case?