I'm creating a dashboard in nextjs14 (App route)

I wanted to create the dashboard with support for multiple languages.
All the solutions I see on the internet are translation with routes (/en, /pt). I didn't want any of that, as it's a webapp.

For example, I wanted to save the user's language in cookies and show the page with the language set in cookies.

I've tried several ways, I can't do it.

Can anyone who has done this kind of thing guide me on where I should go?