History of Swedish

In the 9th century, Old Norse began to diverge into Old West Norse (Norway and Iceland) and Old East Norse (Sweden and Denmark). In the 12th century, the dialects of Denmark and Sweden began to diverge, becoming Old Danish and Old Swedish in the 13th century. All were heavily influenced by Middle Low German during the medieval period. Though stages of language development are never as sharply delimited as implied here, and should not be taken too literally, the system of subdivisions used in this article is the most commonly used by Swedish linguists and is used for the sake of practicality.

In the 8th century, the common Germanic language of Scandinavia, Proto-Norse, had undergone some changes and evolved into Old Norse. This language began to undergo new changes that did not spread to all of Scandinavia, which resulted the appearance of two similar dialects, Old West Norse (Norway and Iceland) and Old East Norse (Denmark and Sweden).

Old East Norse is in Sweden called Runic Swedish and in Denmark Runic Danish, but until the 12th century, the dialect was the same in the two countries. The dialects are called runic because the main body of text appears in the runic alphabet. Unlike Proto-Norse, which was written with the Elder Futhark alphabet, Old Norse was written with the Younger Futhark alphabet, which only had 16 letters. Due to the limited number of runes, some runes were used for a range of phonemes, such as the rune for the vowel u which was also used for the vowels o, ø and y, and the rune for i which was also used for e.

A change that separated Old East Norse (Runic Swedish/Danish) from Old West Norse was the change of the diphthong æi (Old West Norse ei) to the monophthong e, as in stæin to sten. This is reflected in runic inscriptions where the older read stain and the later stin. There was also a change of au as in dauðr into ø as in døðr. This change is shown in runic inscriptions as a change from tauþr into tuþr. Moreover, the øy (Old West Norse ey) diphthong changed into ø as well, as in the Old Norse word for "island".

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