It's a semantically less destructive solution than ScandinavianFoldingFilter, most useful when a person with a Norwegian or Danish keyboard queries a Swedish index and vice versa. This filter does not the common Swedish folds of å and ä to a nor ö to o.
blåbærsyltetøj == blåbärsyltetöj == blaabaarsyltetoej but not blabarsyltetoj räksmörgås == ræksmørgås == ræksmörgaos == raeksmoergaas but not raksmorgas