Norwegian language even it has quite short history developed one of the most complex dialects systems. It’s as complicated as Swedish language dialects system and can cause a headache, not only for people who are trying to learn that Scandinavian language but for native Norwegians as well.
Being historically closer to Faroese and Icelandic, Norwegian took a significant part from Danish and Swedish as well. Almost every Scandinavian languages look and sound similar to neophytes, but this is just the first look. Even being in the same North Germanic group, every speech is different.
The main feature of Scandinavian dialects: people from one country but separate regions not only speak differently but also use different grammatic and syntax rules. Isolated specific of areas causing this dialectic variety. It’s possible to divide Norwegian dialects into five (four primary and one often neglectable) groups: Northern Norwegian (Nordnorsk), Western Norwegian (Vestlandsk), Central Norwegian (Trøndersk) and Eastern Norwegian (Østnorsk). The fifth category is the united group of various country dialects (Innlandsmål). Also sometimes people add Midland Norwegian (Midlandsmål) and South Norwegian (Sørlandsk) to that list. Dividing dialects into West and East groups is possible.
Written Norwegian is also has somewhat complicated and unclear system. There are two official written languages and two unofficial, but also popular and widely used. It’s possible to spread them on the scale from “conservative” to “radical” in that way: Riksmål (National Language), Bokmål (Book Tongue), Høgnorsk (High Norwegian) and Nynorsk (New Norwegian). Bokmål and Nynorsk are official written languages.
Bokmål is the most popular form of written language: it’s the primary option to learn in various Norwegian language schools. Learning the other types and dialects is the secondary goal of Norwegian lovers. You can achieve this goal by completing Bokmål program.
For more information read here.