Feature summary (what you would like to be able to do and where):

An instance of Z60 should contain not only a language code (Z60K1, most likely compliant with bcp47) and aliases thereof (Z60K2), but an identifier for the Wikidata item for that language (as Z60K3 most likely).

Use case(s) (list the steps that you performed to discover that problem, and describe the actual underlying problem which you want to solve. Do not describe only a solution):

Keys into multilingual Z12/texts and Z32/stringsets on Wikifunctions are represented by ZObject identifiers, but the indirect mapping of such identifiers to Wikidata items via language codes is prone to error in many circumstances, due not just to differences in the availability of language codes in different parts of the Wikimedia universe but also to how those language codes are used between those parts where those codes are available. It therefore would alleviate such errors to make a mapping from language objects to Wikidata items explicit within those objects.

There are some specific scenarios where a set of language objects sharing the same set of Wikidata lexemes would be assisted by having a Wikidata item key, such that a reference to the same item on multiple language objects would help establish a link between them:

• different script variants of a language, which may have divergent language codes (e.g. Z1657/pa and Z1083/pnb for Punjabi);
• different romanization standards for a language (e.g. those represented by the Wikidata items Q559173 and Q56929 for Z1221/nan, in addition to Z1647/nan-hani); and
• different regional variants for a language (e.g. Z1003/es, Z1127/es-150, Z1547/es-419, and Z1133/es-mx).

Benefits (why should this be implemented?):

Functions that operate with respect to particular languages can, for example, choose lexemes based on the Wikidata item field and choose representations on those lexemes' forms based on the code field.

(tfsl currently deals with languages as code-item pairs, and code in Ninai and Udiron uses the existence of these pairs extensively.)