Thread:Support/Plural rule changes for many languages

MediaWiki is upgrading its plural rules to match CLDR version 26. The updates include incompatible changes for plural forms in Russian, Prussian, Tagalog, Manx and several languages that fall back to Russian. In addition there are minor changes for other languages.

In January 2014, CLDR 24 had introduced several changes in the plural forms for some of these languages, including Russian, and we had updated MediaWiki's plural rules to comply with the CLDR standard. Some of these changes are now being reverted. Below is a detailed explanation of the changes.

For the migration period, from Monday, 27th October 2014 to Thursday 6th November 2014, LocalisationUpdate is disabled at Wikimedia wikis to reduce the chance of ungrammatical translations being displayed in the interface. Translators are requested to update translations.

Russian and language using Russian as fallback
Languages affected: Russian (ru), Abkhaz (ab), Avaric (av), Bashkir (ba), Buryat (bxr), Chechen (ce), Crimean Tatar (crh-cyrl), Chuvash (cv), Inguish (inh), Komi-Permyak (koi), Karachay-Balkar (krc), Komi (kv), Lak (lbe), Lezghian (lez), Eastern Mari (mhr), Western Mari (mrj), Yakut (sah), Tatar (tt), Tatar-Cyrillic (tt-cyrl), Tuvinian (tyv), Udmurt (udm), Kalmyk (xal).

CLDR 24 plural forms for Russian were:
 * Form 1: @integer 1, 21, 31, 41, 51, 61, 71, 81, 101, 1001, …
 * Form 2: @integer 0, 5~19, 100, 1000, 10000, 100000, 1000000, …
 * Form 3: @integer 2~4, 22~24, 32~34, 42~44, 52~54, 62, 102, 1002, … @decimal 0.0~1.5, 10.0, 100.0, 1000.0, 10000.0, 100000.0, 1000000.0, …

This has been changed to :
 * Form 1: @integer 1, 21, 31, 41, 51, 61, 71, 81, 101, 1001, …
 * Form 2: @integer 2~4, 22~24, 32~34, 42~44, 52~54, 62, 102, 1002, …
 * Form 3: @integer 0, 5~19, 100, 1000, 10000, 100000, 1000000, …
 * Form 4: @decimal 0.0~1.5, 10.0, 100.0, 1000.0, 10000.0, 100000.0, 1000000.0, …

Plurals in translations for affected languages have been updated automatically where possible. Translators are requested to check all messages containing plurals, starting from those which have been marked as outdated.

Prussian
Prussian (prg) now follows the same rules as Latvian (lv):
 * Form 1: @integer 0, 10~20, 30, 40, 50, 60, 100, 1000, 10000, 100000, 1000000, … @decimal 0.0, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0, 100.0, 1000.0, 10000.0, 100000.0, 1000000.0, …
 * Form 2: @integer 1, 21, 31, 41, 51, 61, 71, 81, 101, 1001, … @decimal 0.1, 1.0, 1.1, 2.1, 3.1, 4.1, 5.1, 6.1, 7.1, 10.1, 100.1, 1000.1, …
 * Form 3: @integer 2~9, 22~29, 102, 1002, … @decimal 0.2~0.9, 1.2~1.9, 10.2, 100.2, 1000.2, …

Translators are requested to update all translations containing plural rules. Those translations have been marked as outdated.

Tagalog
Tagalog (tl) has new rules as follows:
 * Form 1: @integer 0~3, 5, 7, 8, 10~13, 15, 17, 18, 20, 21, 100, 1000, 10000, 100000, 1000000, … @decimal 0.0~0.3, 0.5, 0.7, 0.8, 1.0~1.3, 1.5, 1.7, 1.8, 2.0, 2.1, 10.0, 100.0, 1000.0, 10000.0, 100000.0, 1000000.0, …
 * Form 2: @integer 4, 6, 9, 14, 16, 19, 24, 26, 104, 1004, … @decimal 0.4, 0.6, 0.9, 1.4, 1.6, 1.9, 2.4, 2.6, 10.4, 100.4, 1000.4, …

Translators are requested to update all translations containing plural rules. Those translations have been marked as outdated.

Manx
Manx (gv) has a new (fourth) form for decimals. New rules are as follows:
 * Form 1: @integer 1, 11, 21, 31, 41, 51, 61, 71, 101, 1001, …
 * Form 2: @integer 2, 12, 22, 32, 42, 52, 62, 72, 102, 1002, …
 * Form 3: @integer 0, 20, 40, 60, 80, 100, 120, 140, 1000, 10000, 100000, 1000000, …
 * Form 4: @decimal 0.0~1.5, 10.0, 100.0, 1000.0, 10000.0, 100000.0, 1000000.0, …
 * Form 5: @integer 3~10, 13~19, 23, 103, 1003, …

Translators are requested to update all translations containing plural rules. Those translations have been marked as outdated.

Other languages

 * In Mirandese (mwl), Portuguese (pt) and Brazilian Portuguese (pt-br), the first form now also includes zero.
 * In Uyghur (ug), Lower Sorbian (dsb) and Upper Sorbian (hsb), support for decimals was added.
 * In Asturian (ast) and Western Frisian (fy), the first form is no longer used for decimals.

Translators are encouraged to review translations with plural forms and update them where necessary. Because the changes have been minor, we have not marked those translations as outdated.