Learn Icelandic: Maðurinn er grannur.

In Icelandic, the word for "the" is not a separate word like in English. Instead, it gets attached to the end of the noun. The base word is maður (man), and -inn is the masculine ending for "the", giving us maðurinn (the man).

Why does the adjective grannur end in "-ur"?

Adjectives in Icelandic must match the gender of the noun they describe. Because maðurinn is a masculine noun in the subject position, the adjective takes the standard masculine ending -ur.

How would this sentence change if we were talking about "the woman"?

The word for woman is kona, which becomes konan (the woman). The adjective must also change to its feminine form. The sentence becomes Konan er grönn (The woman is slim). Notice how the vowel in the adjective shifts from "a" to "ö" to match the feminine gender!