structural:expansion, quality:correction, linguistic:paraphrasing, quality:corruption, linguistic:voice_change
Literature and language

The most important primary sources on the Vikings are contemporary texts from Scandinavia and regions where the Vikings were active. Writing in Latin letters was introduced to Scandinavia with Christianity, so there are few native documentary sources from Scandinavia before the late 11th and early 12th centuries. The Scandinavians did write inscriptions in runes, but these were usually very short and formulaic. Most contemporary documentary sources consist of texts written in Christian and Islamic communities outside Scandinavia, often by authors who had been negatively affected by Viking activity.

Later writings on the Vikings and the Viking Age can also be important for understanding them and their culture, although they need to be treated cautiously. After the consolidation of the church and the assimilation of Scandinavia and its colonies into mainstream medieval Christian culture in the 11th and 12th centuries, native written sources began to appear in Latin and Old Norse. In the Viking colony of Iceland, extraordinary vernacular literature blossomed in the 12th through 14th centuries, and many traditions connected with the Viking Age were written down for the first time in the Icelandic sagas. A literal interpretation of these medieval prose narratives about the Vikings and the Scandinavian past is doubtful, but many specific elements remain worthy of consideration, such as the great quantity of skaldic poetry attributed to court poets of the 10th and 11th centuries, the exposed family trees, the self-images, and the ethical values that are contained in these literary writings.

Indirectly, the Vikings have also left a window open onto their language, culture and activities, through many Old Norse place names and words found in their former sphere of influence. Some of these place names and words are still in direct use today, almost unchanged, and shed light on where they settled and what specific places meant to them. Examples include place names like Egilsay (from Eigils ey meaning Eigil's Island), Ormskirk (from Ormr kirkja meaning Orms Church or Church of the Worm), Meols (from merl meaning Sand Dunes), Snaefell (Snow Fell), Ravenscar (Ravens Rock), Vinland (Land of Wine or Land of Winberry), Kaupanger (Market Harbour), Tórshavn (Thor's Harbour), and the religious centre of Odense, meaning a place where Odin was worshipped. Viking influence is also evident in concepts like the present-day parliamentary body of the Tynwald on the Isle of Man.

Many common words in everyday English language stem from the Old Norse of the Vikings and give an opportunity to understand their interactions with the people and cultures of the British Isles. In the Northern Isles of Shetland and Orkney, Old Norse completely replaced the local languages and over time evolved into the now extinct Norn language. Some modern words and names only emerge and contribute to our understanding after a more intense research of linguistic sources from medieval or later records, such as York (Horse Bay), Swansea (Sveinn 's Isle) or some of the place names in Normandy like Tocqueville (Toki's farm).

Linguistic and etymological studies continue to provide a vital source of information on the Viking culture, their social structure and history and how they interacted with the people and cultures they met, traded, attacked or lived with in overseas settlements. A lot of Old Norse connections are evident in the modern-day languages of Swedish, Norwegian, Danish, Faroese and Icelandic. Old Norse did not exert any great influence on the Slavic languages in the Viking settlements of Eastern Europe. It has been speculated that the reason for this was the great differences between the two languages, combined with the Rus Vikings' more peaceful businesses in these areas, and the fact that they were outnumbered. The Norse named some of the rapids on the Dnieper, but this can hardly be seen from modern names.