Declaring language in HTML header

Hi I would like to declare my language in the header, for SEO optimisation. Is this possible?

<html lang="en-NL">

Hi @hello42069 , I don’t have an answer to your question but you can look into the site’s Advanced SEO settings and see if you can control it from there or if it already does it for you automatically:

Mines has the lang=“en” within the head without me having to adjust anything.

You can add additional meta tags like mentioned here: