Iceland and the Nordic Council's official language, Icelandic forms part of the West Scandinavian set of North Germanic languages. Icelandic's origins are in the Norse speech that Norwegian settlers brought to Iceland in the ninth and 10th centuries. In the Middle Ages, skaldic poems, sagas, and other types of literature were written in Old Icelandic, or Old Norse, as it's better known.
Today, the whole population of Iceland (around 330,000) speaks Icelandic. Modern-day Icelanders can still easily read Old Icelandic literature since little has changed in grammar and parts of speech. Pronunciation, on the other hand, has actually undergone many changes since the Old Norse era.