Questions & Answers about Ég fylli glasið með vatni.
Why is glasið used instead of glas?
glasið is the definite form of glas (“glass”), meaning “the glass.” In Icelandic you attach a suffix to mark definiteness. Here -ið is the neuter singular definite article. If you meant “a glass,” you would simply say glas (accusative indefinite).
Why is vatni in this form?
The base form is vatn (“water”). Because the preposition með (“with”) always takes the dative case, vatn becomes vatni (dative singular). We don’t use vatnið (“the water”) here because the sentence speaks of water in general, not “the water.”
What case is glasið in and how can I tell?
glasið is the direct object of the verb and therefore in the accusative case. For neuter strong nouns like glas, the accusative singular form is spelled exactly like the nominative. The -ið still shows definiteness even though the case ending itself is zero.
Why is the verb fylla changed to fylli here?
fylli is the 1st person singular present indicative form of fylla (“to fill”). In many Icelandic verbs you drop the infinitive ending -a and add -i in the present tense. The full present-tense paradigm of fylla is:
• Ég fylli
• Þú fyllir
• Hann/hún fyllir
• Við fyllum
• Þið fyllið
• Þeir/þær/þau fylla