The LC-PCC Policy Statement on Form of Language Names (LC-PCC PS for 126.96.36.199) needs review to work better in a post-MARC environment.
The MARC bibliographic and holdings formats mandate use of a specific list of language codes in fixed-length data elements: http://www.loc.gov/marc/languages/. The corresponding labels of these codes, with certain modifications, are used as authoritative forms of language names. In contrast RDA, and thus RDA/RDF, is more open. For example, for Language of Expression (6.11), RDA instructs “Record the language or languages of the expression using an appropriate term or terms in a language preferred by the agency creating the data. Select terms from a standard list of names of languages, if available.”
The LC-PCC Policy Statement on Form of Language Names is written for MARC. It assumes that language names are recorded as text strings and gives instructions on how to modify labels of language codes to create authoritative forms.
At least two problems need to be resolved.
1) In linked data, URIs are preferred to text strings, so explicit provision should be made in the PS for using them. It seems reasonable for PCC to adopt a best practice here. One option is to use URIs from the MARC Code List for Languages, e.g. http://id.loc.gov/vocabulary/languages/eng. Another option is to use ISO 639-2 (Codes for the representation of names of languages—Part 2: Alpha-3 code), whose codes are compatible with the MARC List: for example, http://id.loc.gov/vocabulary/iso639-2/eng. A third option is to use ISO 639-1 (Codes for the representation of names of languages—Part 1: Alpha-2 code): for example, http://id.loc.gov/vocabulary/iso639-1/en. Two letter codes are widely used in other web applications including the LC BIBFRAME converter. This question of thesaurus for URIs of language codes needs thought and discussion to arrive at the best choice.
2) There is still a need for an authoritative list of language names for PCC use. Even if URIs rather than text strings are used for Language of Expression, the instructions for forms of language names in LC-PCC PS for 188.8.131.52 are referred to from other policy statements, such as that for 184.108.40.206. The PS for 220.127.116.11 needs to be rewritten more broadly as instructions for creating forms of language names rather than as a way to provide text strings for RDA 18.104.22.168.