This code system http://terminology.hl7.org/CodeSystem/iso639-2ret defines many codes, but they are not represented here

 <status value="retired"/> <experimental value="false"/> <date value="2019-03-20T00:00:00-04:00"/> <publisher value="TBD - External Body"/> <description value="Codes for the Representation of Names of Languages Part 2: Alpha-3 Code. Used as part of the IETF 3066 specification for languages throughout the HL7 specification. *DeprecationComment:* This code system is being deprecated, as the OID identifying it has been replaced with the correct ISO OID of 1.0.639.2"/> <caseSensitive value="true"/> <content value="not-present"/> </CodeSystem>