Breakdown of Nei, ég er ekki búinn með rúlluna.
ég
I
nei
no
ekki
not
vera búinn með
to be finished with / to have run out of
Questions & Answers about Nei, ég er ekki búinn með rúlluna.
Why is rúlluna in the accusative case here?
The phrase vera búinn með (to be finished with a consumable or a tool) requires the accusative case for the object you are finishing. Because rúlla is a feminine noun, its definite accusative form is rúlluna.
If a woman were saying this sentence, would búinn change?
Yes, because búinn acts as an adjective that must agree with the subject (ég) in gender and number. A male speaker says búinn, a female speaker says búin, and a non-binary speaker says búið.
I remember learning vera búinn að for completed actions. Why do we use með instead of að here?
You use vera búinn að followed by a verb to say you have finished an action, like painting. However, you use vera búinn með followed by a noun when you are finished using a physical object or consuming something, like this roller.
What exactly does rúlluna refer to in this context?
Rúlla (a roll or roller) is a versatile word that can mean a paint roller, a roll of toilet paper, or even a sushi roll. Since all of these are physical objects you either finish using or finish eating, they pair perfectly with the phrase vera búinn með.