Learn Icelandic: Annar parturinn er gamall, en hinn er úr frumritinu. - One part is old, but the other is from the original.

When talking about exactly two specific things, Icelandic uses annar for the first and hinn for the second. You use einn ... annar when picking two items out of a larger, unspecified group.

Why does parturinn have the definite article suffix (-inn) when the English says 'One part'?

In Icelandic, when annar means 'one of two,' the noun attached to it must be in the definite form. Even though we say 'One part' in English, the Icelandic grammar literally functions more like 'The one part.'

Why are Annar, gamall, and hinn all in the masculine form?

They all need to agree in gender, number, and case with the noun they refer to, which is the masculine word partur (part). Since it is singular and the subject of the sentence (nominative case), the pronouns and adjectives take their masculine, singular, nominative forms.

Why is frumritinu in the dative case here?

The preposition úr (from/out of) always forces the following noun into the dative case. The root word is the neuter noun frumrit (original document), which becomes frumritinu when definite and dative.