Norwegian (norsk) is a North Germanic language spoken mainly in Norway, where it is the official language. Along with Swedish and Danish, Norwegian forms a dialect continuum of more or less mutually intelligible local and regional varieties; some Norwegian and Swedish dialects, in particular, are very close. These Scandinavian languages, together with Faroese and Icelandic as well as some extinct languages, constitute the North Germanic languages. Faroese and Icelandic are not mutually intelligible with Norwegian in their spoken form because continental Scandinavian has diverged from them. While the two Germanic languages with the greatest numbers of speakers, English and German, have close similarities with Norwegian, neither is mutually intelligible with it. Norwegian is a descendant of Old Norse, the common language of the Germanic peoples living in Scandinavia during the Viking Era. Today there are two official forms of written Norwegian, Bokmål (literally "book tongue") and Nynorsk ("new Norwegian"), each with its own variants. Bokmål developed from the Dano-Norwegian koiné language that evolved under the union of Denmark-Norway in the 16th and 17th centuries, while Nynorsk was developed based upon a collective of spoken Norwegian dialects. Norwegian is one of the two official languages in Norway. The other is Sami, spoken by some members of the Sami people, mostly in the Northern part of Norway. Norwegian and Sami are not mutually intelligible, as Sami belongs to the Finno-Ugric group of languages. Sami is spoken by less than one percent of people in Norway. Norwegian is one of the working languages of the Nordic Council. Under the Nordic Language Convention, citizens of the Nordic countries who speak Norwegian have the opportunity to use their native language when interacting with official bodies in other Nordic countries without being liable to any interpretation or translation costs.