Learn Icelandic: Ert þú frá Reykjavík?

While many Icelandic nouns change their endings in the dative case, some don't. The city name Reykjavík happens to look exactly the same in the nominative, accusative, and dative cases! It only changes in the genitive case (becoming Reykjavíkur). So, the word is successfully doing its job in the dative case here, even though the spelling stayed the same.

Does the preposition frá always take the dative case?

Yes! Unlike some Icelandic prepositions that switch between cases depending on whether there is active movement or a static location (like í or á), frá is strictly a dative preposition. Any noun or pronoun immediately following it will always be in the dative case.

Why is the verb ert at the very beginning of the sentence?

Just like in English, Icelandic swaps the subject and the verb to turn a statement into a yes/no question. The standard statement 'You are' is Þú ert, but to ask 'Are you?', you simply flip the word order to Ert þú?

Could I just say Er þú frá Reykjavík?