Creating language package options

Question

This is essentially the same question: Write a class with language dependent strings. But I didn't find any solutions that worked.

I'm trying to create a package where languages are package options, like so:

\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{mypackage}[2019]
\RequirePackage[utf8]{inputenc}                  
\RequirePackage{babel}                           

\DeclareOption{nynorsk}{
    \PassOptionToPackage{main=nynorsk}{babel}
        %\AtEndOfClass{\main@language{nynorsk}}
}        % Gir pakken med nynorsk babel
\DeclareOption{bokmål}{
    \PassOptionToPackage{main=norsk}{babel}
        %\AtEndOfClass{\main@language{norsk}}
}           % Gir pakken med bokmål babel
\DeclareOption{english}{
    \PassOptionToPackage{main=english}{babel}
        %\AtEndOfClass{\main@language{english}}
}         % Gives the package with english babel
\DeclareOption*{\PackageWarning{examplepackage}{Unknown ‘\CurrentOption’}} % for unknown input
\ProcessOptions\relax
\endinput

In a document it would look something like this:

\documentclass{article}
\usepackage[english]{mypackage}

\beging{document}
Hello, this is a document
\end{document}

I get this error on the line \usepackage[english]{mypackage} in the document:

LaTeX Error: Unknown option `english' for package `mypackage*. Missing
= inserted for \infum. Missing numer,treated as zero.

and on the line with \begindocument I get this error:

LaTeX error: \RequirePackage or \LoadClass in Options section

So how can I create a multilingual package with language options?

edit: What I try to do is including the babel package in mypackage such that I can write:

\usepackage[english]{mypackage}

instead of:

\usepakckage{mypackage}
\usepackage[english]{babel}

Answer 1

Package options cannot be applied after the package has been loaded, so move \RequirePackage{babel} at the end.

Second, don't use non-ASCII chars (like å).

And third, the name is \PassOptionsToPackage (note the “s”).