locale

// usage
randBox.locale()
randBox.locale({region: true})

Generate a random ISO-639-1 language code

randBox.locale();
=> 'ca'

Generate a random IETF region code

randBox.locale({region: true});
=> 'es-EA'

Note, the language codes comes from the ISO-639-1 spec  and the region codes come from IETF standard