ISO 639-1 is the first part of the ISO 639 international-standard language-code family. ISO 639-1 provides two-character lowercase alphabetic strings that serve as identifiers of languages. The list contains approximately 180 discrete codes. All ISO 639-1 languages also have ISO 639-2 three-character code representations. These codes are linked to codes for the same languages in ISO 639-2 and the MARC Language Codes.