"ISO 6391-1" is probably a typo for "ISO 639-1". They are not country-codes but language codes.
Furthermore, how is "language of dataset" defined?
If it is a set of texts in a specific language, then ISO 639-1 is not good enough for linguistics. You'd need ISO 639-3 at a minimum, there are after all still more than 676 languages on this planet. But since a single dataset from linguistics can cover multiple languages (comparative datasets, for instance), a single field is not enough.
So: what is the actual purpose of dataset.language?
"ISO 6391-1" is probably a typo for "ISO 639-1". They are not country-codes but language codes.
Furthermore, how is "language of dataset" defined?
If it is a set of texts in a specific language, then ISO 639-1 is not good enough for linguistics. You'd need ISO 639-3 at a minimum, there are after all still more than 676 languages on this planet. But since a single dataset from linguistics can cover multiple languages (comparative datasets, for instance), a single field is not enough.
So: what is the actual purpose of dataset.language?