Norwegian (Bokmål) is available in the Immersive Reader in Word Online, OneNote Online, Outlook.com, and Outlook web.
Kawabata, at the moment this functionality works automatically in Word Online, OneNote Online, Outlook.com and Outlook Web App. If you'd like for it to work in OneNote Desktop, you would need to install an English voice (https://support.office.microsoft.com/en-us/article/How-to-download-Text-to-Speech-languages-for-Windows-4c83a8d8-7486-42f7-8e46-2b0fdf753130?ui=en-US&rs=en-US&ad=US), have Text be marked as English in your document and then select that text in the Reader and choose the English voice from the Voice dropdown. Hope that helps.
The Immersive Reader is now available in OneNote Online, Word Online and OWA!