Old Norse was the Germanic language spoken by the inhabitants of Scandinavia and their overseas settlements during the Viking Age, until about 1300. It evolved from the older Proto-Norse, in the 8th century.
Because most of the surviving texts are from Medieval Icelandic, the de facto standard version of the language is the Old West Norse dialect, that is Old Icelandic and Old Norwegian. Most speakers of Old Norse, however, spoke the very similar Old East Norse dialect in Denmark and Sweden and their settlements. There was no clear geographical separation between the two dialects. Old East Norse traits were found in eastern Norway and Old West Norse traits were found in western Sweden. In addition, there was also an Old Gutnish dialect, sometimes included in Old East Norse because it was the least known dialect. However there are reasons to consider this a separate branch since it shares traits with both Old West Norse and Old East Norse and also has developed its own. The Icelandic Gray Goose Laws stated that Swedes, Norwegians, Icelanders and Danes all spoke the same language, dǫnsk tunga. In the eastern dialect, which was spoken in Sweden and Denmark, this would have been dansk tunga and this translates as the "Danish tongue". It was also called norrœnt mál ("Nordic language").
It has been said that old Norse was mutually intelligible with Old English, Old Saxon and Old Low Franconian, which however may be an overstatement.citation needed] Although the languages were closer then, a Scandinavian of the time may not have understood an Anglo-Saxon better than a present day Englishman understands Dutch.citation needed]
Old Norse gradually evolved into the modern North Germanic languages: Icelandic, Faroese, Norwegian, Danish and Swedish. Modern Icelandic is the descendant that has diverged the least from Old Norse. In its normalised written form based off the Old Norse/modern Icelandic phoneme system, Old Norse is understandable to modern day Icelandic-speakers with only minute differences in spelling as well as semantics and word order. Had it been spoken during the Old Norse era, its modern pronunciation and extended vocabulary aside, it would have been considered nothing more than the most differentiated of all Norse dialects of the time. However, pronunciation, particularly of the vowel phonemes, has changed at least as much as other North Germanic languages. But regarding the phoneme system itself the language still retains more of the Old Norse system of phonemes than do the others as it is more or less identical to the 13th century western Old Norse system of phonemes while all in all being very similar to the more archaic versions found during the later Viking age. The differences are in fact so minute that someone reading a text might need to sift through several sentences before being able to spot a single ancient/modern difference. Faroese retains many similarities but is influenced by Danish, Norwegian, and Gaelic (Scottish and/or Irish). Although Swedish, Danish and the Norwegian languages have diverged the most, they still retain mutual intelligibility. This could be because these languages have been mutually affected by each other, as well as having a similar development influenced by Middle Low German.