Sorry for misunderstanding.
Correct language indication is not about spelling.
Properly specifying languages in the HTML code is about SEO – Search Engine Optimization – and SEM – Search Engine Marketing –
For a good result, it is important to follow the instructions given here:
Google Search Console
Webmaster Tools – Bing
and many more.
When the wrong language is set, the site can get unnecessarily poor ranking in the search engine result.
“Norwegian Bokmål” and “Norwegian Nynorsk” are two different languages.
When you specify the wrong language in the HTML code, you counteract the recommendations given in the links above.