A patent application must be written in Norwegian or English. If you file an application in another language, you will be instructed to translate the application into Norwegian or English. All documents in the application must be in the same language. You cannot change the language of the documents after the application has been submitted.
If you think it is easiest to describe your invention in Norwegian, we recommend that you file the application in Norwegian.
If you file the application in English, it may simplify the work if you are applying for a patent in other countries that accept English as the application language.