Intersection of http://hl7.org/fhir/ValueSet/languages and http://hl7.org/fhir/us/core/ValueSet/simple-language
This is the ValueSet that contains codes in both Common Languages (http://hl7.org/fhir/ValueSet/languages) and Language codes with language and optionally a region modifier (http://hl7.org/fhir/us/core/ValueSet/simple-language).