How are the Scandinavian languages divided into East Scandinavian and West Scandinavian groups?

The Scandinavian languages are categorized into two primary groups based on historical dialectal differences that emerged during the Viking Age and the subsequent development of the Nordic kingdoms.12

• East Scandinavian: This group consists of Danish and Swedish. Historically, this area was characterized by more innovative linguistic features compared to the west. A key development was the monophthongization of the Old Scandinavian diphthongs ei, au, and øy into ē and ø (e.g., steinn becoming stēn). Additionally, the pronoun ek ("I") shifted to jak in this region.12

• West Scandinavian: This group includes Norwegian, Icelandic, and Faroese. This area is considered more conservative, as it retained the original diphthongs and the pronoun ek (which evolved into eg or ég in modern forms) rather than adopting the eastern innovations.12

While these divisions are useful for classification, it is important to note that linguistic transitions between these areas were often gradual rather than abrupt.3