ISO 639-3:2007提供了一个由ISO 639-3注册机构发布的代码，该代码由语言代码元素组成，包含三个字母的语言标识符，用于表示语言。根据ISO 639-3:2007设计的语言标识符适用于广泛的应用，尤其是在计算机系统中，其中可能需要支持已知存在的大量语言。ISO 639-1和ISO 639-2旨在关注世界上所有文献中最常出现的主要语言，而ISO 639-3:2007则试图提供尽可能完整的语言列举，包括活的、灭绝的、古老的和构造的语言，无论是主要的还是次要的、书面的还是非书面的。 因此，ISO 639-3:2007涉及大量鲜为人知的语言。本代码不包括专门为机器使用而设计的语言，如计算机编程语言和重构语言。

ISO 639-3:2007 provides a code, published by the Registration Authority of ISO 639-3, consisting of language code elements comprising three-letter language identifiers for the representation of languages. The language identifiers according to this ISO 639-3:2007 were devised for use in a wide range of applications, especially in computer systems, where there is potential need to support a large number of the languages that are known to have ever existed. Whereas ISO 639-1 and ISO 639-2 are intended to focus on the major languages of the world that are most frequently represented in the total body of the world's literature, ISO 639-3:2007 attempts to provide as complete an enumeration of languages as possible, including living, extinct, ancient and constructed languages, whether major or minor, written or unwritten. As a result, ISO 639-3:2007 deals with a very large number of lesser-known languages. Languages designed exclusively for machine use, such as computer-programming languages and reconstructed languages, are not included in this code.