Norwegians are accustomed to variation and may perceive Danish and Swedish only as slightly more distant dialects. This is because they have two official written standards, in addition to the habit of strongly holding on to local dialects. The people of Stockholm, Sweden and Copenhagen, Denmark have the greatest difficulty in understanding other Scandinavian languages. In the Faroe Islands and Iceland, learning Danish is mandatory. This causes Faroese people as well as Icelandic people to become bilingual in two very distinct North Germanic languages, making it relatively easy for them to understand the other two Mainland Scandinavian languages.