Task Prio Notes:

• Does not affect end users / production
• Does not affect monitoring efforts
• Might affect development efforts
• Affects onboarding efforts
• Does not affect additional stakeholders

Story Writing Notes:

• Two acceptance criteria at least:
  1. Documentation is created (specify location, probably wiki)
  2. Documentation is linked to in relevant places (specify relevant places, probably dev readme)

I was recently putting together something like this. :) Here's what I have for how to actually add a code:

Information needed:

For Wikidata:

• Language code
• Name in English

For language-data (not needed for Wikidata itself, but recommended for consistency):

• Native name
• Script
• Region(s) used: Worldwide, America, Europe, Middle East, Africa, Asia, Pacific

Adding a code for labels (which will automatically add it for monolingual text and lexemes as well):

In mediawiki-extensions-Wikibase:

• add it to getDefaultTermLanguages in WikibaseContentLanguages.php (https://github.com/wikimedia/mediawiki-extensions-Wikibase/blob/master/lib/includes/WikibaseContentLanguages.php)

In operations-mediawiki-config:

• add it to InitialiseSettings.php (https://github.com/wikimedia/operations-mediawiki-config/blob/master/wmf-config/InitialiseSettings.php, section wmgExtraLanguageNames)

Adding a code only for monolingual text:

In mediawiki-extensions-Wikibase:

• add it to getDefaultMonolingualTextLanguages in WikibaseContentLanguages.php (https://github.com/wikimedia/mediawiki-extensions-Wikibase/blob/master/lib/includes/WikibaseContentLanguages.php)

Adding a code only for lexemes:

In mediawiki-extensions-WikibaseLexeme:

• add it to $additionalLanguages in WikibaseLexeme.mediawiki-services.php (https://github.com/wikimedia/mediawiki-extensions-WikibaseLexeme/blob/master/WikibaseLexeme.mediawiki-services.php)
• add it to i18n/language-names/en.json (https://github.com/wikimedia/mediawiki-extensions-WikibaseLexeme/blob/master/i18n/language-names/en.json)

In all cases:

In mediawiki-extensions-cldr:

• check whether it is in CldrNamesEn.php (https://github.com/wikimedia/mediawiki-extensions-cldr/blob/master/CldrNames/CldrNamesEn.php)
• if not, add it to LocalNames/LocalNamesEn.php (https://github.com/wikimedia/mediawiki-extensions-cldr/blob/master/LocalNames/LocalNamesEn.php)

In language-data:

• check whether it is in data/langdb.yaml (https://github.com/wikimedia/language-data/blob/master/data/langdb.yaml)
• if not, add it or file a ticket for it to be added

If it uses a RTL script:

In mediawiki:

• create a messages file in languages/messages/ (https://github.com/wikimedia/mediawiki/tree/master/languages/messages) by copying MessagesEn_rtl.php (https://github.com/wikimedia/mediawiki/blob/master/languages/messages/MessagesEn_rtl.php)

explaining the availability of the names

If you find anyone who truly understands that, do let me know. :)

and an the relation to the CLDR extension.

Wikibase gets localised language names from the CLDR extension. Names provided by CLDR are in the CldrNames directory. We can add things which are missing (or override existing ones) in the LocalNames directory. The CLDR extension falls back to wmgExtraLanguageNames and Names.php, so a name might still be shown for languages not in the CLDR extension if the language is defined in one of those places instead.

Enabling Wikibase label support by explaining why we need to change both Wikibase.git and config files, what each does, and in what order.

Both need to be changed because T273627 is not yet resolved. Most parts of Wikidata fetch languages from one, some parts (see the ticket) still rely on the other. I'm not sure if the order matters, but it doesn't work properly without changing the config so that might be the best one to do first.

Note that for lexemes, while the names on Special:NewLexeme come from the WikibaseLexeme i18n directory, the names given by wbcontentlanguages in the API come from the CLDR extension (which I reported at T322139).

@Nikki this is very informative and helpful. Thank you!

Documentation added to https://www.mediawiki.org/wiki/Manual:Adding_and_removing_languages#Wikibase.

Change 923332 had a related patch set uploaded (by Noa wmde; author: Noa wmde):

[mediawiki/extensions/Wikibase@master] Add a section in the README about adding language codes

https://gerrit.wikimedia.org/r/923332

Change 923335 had a related patch set uploaded (by Noa wmde; author: Noa wmde):

[mediawiki/extensions/WikibaseLexeme@master] Add a section about language code support

https://gerrit.wikimedia.org/r/923335

Change 923332 merged by jenkins-bot:

[mediawiki/extensions/Wikibase@master] Add a section in the README about adding language codes

https://gerrit.wikimedia.org/r/923332

Change 923335 merged by jenkins-bot:

[mediawiki/extensions/WikibaseLexeme@master] Add a section about language code support

https://gerrit.wikimedia.org/r/923335

I linked the documentation from the project description of Language codes as well now.