Hello Mert,
This is an interesting question and depends on a lot of things, among them: type of industry, project, part of the country, company, your experience, client, contract and need for specific expertise. Generally, in the construction industry the contracts are in Norwegian language (some also have an English version as an attachment), however, I have a lot of friends who work in Norway without speaking the language. This again has a different reason in every case: for example some work in international companies, some work on specific contracts where English is a contractual language and some are experts in their field.
The bottom line is, if you plan to move to Norway, I recommend you study Norwegian – as in every country, it is better to speak the local language:-)
Thanks for reading our articles!
Konrad