Wikipedia
Svorsk or Svorska ( portmanteau of "svensk(a)", Swedish, and "norsk(a)", Norwegian) is a term describing a mixture of the Swedish and Norwegian languages.
The term "svorsk" is used to describe the language of someone (almost exclusively a Swedish or Norwegian person) who mixes words from his or her native tongue with the other language. The phenomenon is not uncommon, especially in light of the close business and trade ties between the two countries and the mutual intelligibility between the two languages, the latter in its turn being due to the common ancestry and parallel development of both Norwegian and Swedish from Old Norse (see North Germanic languages). The term originates from the 1970s.
Individual Swedish loanwords and phrases that are assimilated into the Norwegian language are called svecisms (svesismer). This trend has been ongoing since the dissolution of the Dano-Norwegian Union in 1814; however, it gained momentum substantially after the dissolution of the union between Norway and Sweden in 1905 and has been an ongoing phenomenon of Norwegian linguistics, and still is. Indeed, the prominent Norwegian linguist Finn-Erik Vinje characterizes this influx since World War II as a breaking wave.