Language Swedish, Danish, Norwegian, Icelandic and Faroese are all North-Germanic languages developed from the Old Norse spoken in Viking age Scandinavia. A Swede, a Dane and a Norwegian can understand each other with varying degrees of difficulties, but none of them will fully understand Icelandic or Faroese without studying the languages. Finnish is an entirely different case, it's a Finno-Ugric language related to Estonian and Hungarian. There is, however, a Swedish-speaking minority in Finland, which ties it linguistically to Scandinavia. The way this melodic accent is expressed vary quite a lot between different dialects, but the dichotomy exists everywhere having an important role to differentiate between words which otherways would have been confused.
Words derived from two-syllable roots usually have an almost equal stress on both syllables.
Questions are expressed by a rising tone on the second syllable. No one actually speaks Nynorsk for example. Norwegian language has as many dialects as there are cities and villages and valleys and fjords, and there is no way to create a common written language from that. Actually, the truth is somewhat more complex, since Norwegian and Danish have radically simplified their pronunciation and grammar in a way that Swedish has not, but the pronunciation of Danish has subsequently been influenced by that of German, while Swedish and Norwegian have not.