Translations:LibreOffice Localization Guide/33/en
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- Use ISO 639-1 if possible. This happens when the language is spoken in a single country (or there are no major differences between how it is spoken in different countries), or when the ISO code of the language is the same than the ISO code of the country (es, fr).
- Use ISO 639-2 (three letter language code) if no ISO 639-1 (two letter) code exists.
- Use ISO 3166 country code if necessary, to specify versions of languages with the same language code in different countries, such as Spanish in Chile (es-CL), Portuguese in Brazil (pt-BR), or English in the United States (en-US).