Learn Icelandic: Er kaffið kalt eða er það heitt?

Eða (or) is a coordinating conjunction, meaning it links two equal clauses. Because the first half is a question starting with a verb (Er kaffið...), the second half remains a question too. In Icelandic, yes/no questions always start with the verb, so we use the verb-first order er það heitt (is it hot) instead of the statement form það er heitt (it is hot).

Why do the adjectives kalt (cold) and heitt (hot) both end in -t?

Adjectives in Icelandic must match the gender of the noun they describe. The word kaffi is a neuter noun. To describe a neuter noun, most adjectives take a -t ending. If you look these words up in a dictionary, you will usually find their masculine default forms: kaldur and heitur.

Why is the pronoun það used for "it" here?

Það is the neuter pronoun for "it". Because it refers back to the neuter noun kaffið in the second half of the sentence, the pronoun must match its gender.

Where is the word for "the" in kaffið?