Short answers, pulled from the story.
About 390,000 people speak Icelandic, the vast majority living in Iceland. Smaller communities exist in Denmark (about 8,000 speakers), the United States (about 5,000), and Canada (more than 1,400), notably in the Manitoba region known as New Iceland.
Icelandic preserved a four-case synthetic grammar and a conservative vocabulary through a combination of geographic isolation and deliberate linguistic purism. Danish rule from 1536 to 1918 had little effect on the spoken language, and since the late 18th century, official language policy has favored coining new words from Icelandic roots rather than borrowing from other languages.
Yes. Modern Icelanders can follow the sagas of Icelanders and the Poetic Edda, written roughly eight hundred years ago, when presented with updated modern spelling and footnotes. With additional effort, many can also read the original manuscripts directly.
The Icelandic alphabet retains three letters absent from modern English: Þ (thorn) and Ð (eth), which represent the voiceless and voiced "th" sounds respectively, and Æ (ash), which represents the diphthong heard in the English word ride.
The modern Icelandic alphabet was standardized in the 19th century by the Danish linguist Rasmus Rask. His standard was based closely on an orthography first set out in the early 12th century in a document called the First Grammatical Treatise, written by an anonymous author known as the First Grammarian.
Icelandic Language Day is celebrated on the 16th of November each year, since 1995. The date marks the birthday of Jónas Hallgrímsson, a 19th-century Icelandic poet.