Old Norse language

Swedish, Danish, Norwegian, Icelandic and Faroese languages, each with their dialects, are germanic languages in a historical view.

The scandinavian languages with their Germanic origin consequently developed from one and same Germanic language. The language was quite uniform until the end of the first millenium and gradually, around the 14th century the Old Norse dialects were each on its own course. However there were and still are exceptions regarding some dialects spoken in some geographically overlapping areas. Still a few dialects have close to the same prosody or "accent", in Norwegian and Swedish areas around the border.

Although Scandinavia usually means Sweden, Norway and Denmark, it historically, its original meaning implies a geographic area that refers to south Sweden. However today it often includes Iceland, Faroes Islands and even Finland.

Some of the dialects in Norway and Sweden have very old traits and at least one of them should be defined as an own language. More about this later.
It can be mentioned, that there were two major tribes in the early Sweden, Svions and Goths. (Still today, the names svear and götar are still used, mostly in a historical context although it still aparts dialect regions.)

Scandinavian history

In the history of mankind in Scandinavia, there were people in Denmark and southern Sweden early as 12000-9000 f.Kr. Among the findings is the bromme culture.
A much later culture is the funnelbeaker culture, around 4000-2700 bc. The north of Scandinavia became inhabitated ca 12000 years ago but it is not known whether the sami people are the ancestors from there or not.

From Proto-germanic to Old-Norse
The first germanic language in Scandinavia was on a level called Proto-germanic, which was about the same language as for that or those that later diverged into the other germanic languages, the west group; English, Dutch, German. And the east group; Danish, Norwegian, Icelandic, Faroese, Swedish and the extinct Gothic language as well as other extinct East germanic languages.

However, since the area of South Denmark, Sweden, northern Germany was inhabited down to thousands of years BC, the Proto-germanic language, of course, had an earlier history, probably shared with other languages in the area. An article in Wikipedia gives weight to the matter, called Germanic Parent Language with a related discussion.

Proto Norse language

The first language that then evolved in Scandinavia, from Proto-germanic, is called Proto-Norse. Its period is believed to span between ca the 3rd and 7th century. It underwent changes that led to the Old Norse which appeared around the time as the "viking" period began. Unless the Proto-Norse had already divided into west and east as it developed into Old Norse, this west and east division was already established in the 9th century.

Old Norse language

Yes, there were probably dialects in the beginning or early in the time of Old Norse, what would become west and east old norse.
Old East Norse in Denmark, Sweden and England.
Old West Norse in Norway, Iceland, Faroese Islands, Greenland, Orkney and Shetland.
On Orkney and Shetland, the language that evolved there is the Norn Language.

On the Swedish island called Gotland, there was by some defined as a third norse variation, called Old Gutnish
While Old West Norse became relatively unchanged in the Icelandic and Faroese languages, Old West and East Norse further diverged into what later became Danish, Swedish, Norwegian. This diversion took place a little faster in Denmark, maybe in that the change in Danish as by Low German language, influenced the Swedish and Norwegian languages.
The Old Gutnish got more assimilated into Swedish what is today a modern Gutnish. The dialects in the modern Gutnish have kept an own character almost until today, though at risk of further disappearing due to the the effects of the society etc.
Among the dialects in Denmark, Norway and Sweden, the dialects with oldest traits are to be found in Norway and especially in Sweden. In Sweden there is one dialect, Elfdalian/Älvdalska with such old features it would be better not to call it a swedish dialect but to call it an Old East Norse dialect, though influenced by swedish, of course.

Other locations where Old east Norse and Old west norse have been spoken;
Vikings sailed to many places but they did not establish lasting settlements everywhere.
Overview of the viking expansion or here (shorter).

Scotland and England
Old norse was spoken in Scotland and the eastern coast of England after the danish viking settlement. Most danes therefore Old east norse though there were a few norwegian settlers as well, with a old west norse.
The viking settlement first began ca AD 865 and kept on until the 9th and 10th centuries. More info here. Due to this circumstance, there was a norse influence on the old english language. While they certainly were using Old Norse to eachother, the scandinavian settlers probably adapted to the old english around so that their children became more and more old english speaking. However their influence had such an impact so many words in english are of old norse origin. Some Old Norse words have survived in the dialects of Northeastern England.
(There are other english words that are close to scandinavian words simply because they both are germanic languages, therefore have remained close since the time of proto-germanic language.)
Norwegian and Danish vikings sail to the British Isles.

Shetland / Orkney
Old norse was also spoken on Orkney and Shetland. People from west Norway first came there in the 8th and 9th century. This language, with dialects, called Norn got extinct in the 19th century, after several hundred years of decline. During the norn episode, Orkney and Shetland had their own dialects. In both dialect groups, norn became mixed with english and scottish words. If a word was re-placed to the english word within the Orkney dialect, the same word could still be of the norn origin within the Shetland dialect, and vice versa.
Norn Language.

Greenland

A few people from west Norway settled down in south Greenland around AD 985 or 986 as to be read about here or here. On 2 locations, the eastern settlement that was populated by as many as 4000 people and the western settlement that only held up to about 1000 people. After a decline in the 14th century, the smaller western settlement was abandoned in 1350 and the eastern around 1410-1420.

Greenlandic Norse Language

Eastern Europe and Russia

Vikings settled down at coasts at the Baltic Sea and in Russia. There is an extensive amount of history in this field so until now, more info can be found in the links below.
Some russian names with Scandinavian origin;
Oleg - Helgi (~ holy) (Nowadays Helge in Sweden)
Olga - Helga (~ holy)
Igor - Ingvar (Man, or warrior of the god Ing). The end -var is probably identical to were*.

The Varangians
The Varangians Shorter)

External links

Old Norse language
Proto Norse language
Old Norse article in the Swedish language article
Old East Norse
Old West Norse