Questions & Answers about Ég kveikti á vasaljósinu en ég sá ekki nokkurn inni.
Why is nokkurn in the masculine accusative form here?
When nokkur means 'anybody' or 'anyone' in a general sense, it defaults to the masculine gender because it refers to a person of unknown gender. It is in the accusative case (nokkurn) because it is the direct object of the verb sjá (to see).
Can I use neinn instead of nokkurn in this sentence?
Why is vasaljósinu (the flashlight) in the dative case?
The phrasal verb kveikja á (to turn on) requires its object to be in the dative case. Since vasaljós is a neuter noun, attaching the dative definite article ('the') makes it vasaljósinu.
Why use inni instead of inn at the end of the sentence?
In Icelandic, there is a strict difference between stationary location and motion. Because the sentence describes a stationary state (anyone being located inside), we use the location word inni. If the sentence were about someone walking inside, you would use the motion word inn.