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When we register in TMDb, we must determine a Default Language and a Secondary Language.
In the dropdown of languages we have 292 options, including "none".
I believe the list of languages is based on the ISO 639-1 table.
https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes
And the list of countries is based on the ISO 3166-1 or ISO 3166-2 table.
https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2
https://en.wikipedia.org/wiki/ISO_3166-2
The code should be: language code ISO 639-1 - COUNTRY CODE ISO 3166-1 or 2.
es-ES, es-MX, pt-BR, hi-IN, etc...
I assume all are valid for entering movie data.
This needs to be confirmed by a Moderator.

Hi @yveslym4,

Assuming you're looking for this from a data perspective (API), you can find the following lists useful:

• Languages: https://developers.themoviedb.org/3/configuration/get-languages
• Countries: https://developers.themoviedb.org/3/configuration/get-countries
• Primary translations: https://developers.themoviedb.org/3/configuration/get-primary-translations

Could I request you to use the ISO 639-3 list instead of the ISO 639-1 list? I tried to add a Dagbani film today, but Dagbani (with more than 1 million native speakers in Ghana) is not listed in ISO 639-1.

I'd love to update the ISO codes but any changes to existing data would break the thousands of apps using TMDb. Because of this, migrating ISO's is a particularly tricky thing to do and not something I have time to look at in the near of future.