Issue #2240459 by Gábor Hojtsy, penyaskito | LoMo: Fixed Applying default language fallback rules to interface translation has impressively bad results.

Issue #2246665 by jaredsmith, martin107, YesCT, filijonka, tstoeckler: Typehint with Drupal\Core\Language\LanguageInterface instead Drupal\Core\Language\Language.

Issue #2219499 by Berdir, alexpott, Gábor Hojtsy, vijaycs85, swentel: Generalize language config override responsibility.

Issue #2190643 by Berdir, amateescu, Xano, yched: Serializing the container is a very very bad idea, let's prevent it?.

Issue #1862202 by plach, Berdir, katbailey, ParisLiakos, alexpott, chx, sun, larowlan, Gábor Hojtsy, cosmicdreams, vijaycs85, YesCT, penyaskito, andypost, Albert Volkman, joelpitett: Objectify the language system.

Issue #2098119 by beejeebus, alexpott, chx: Replace config context system with baked-in locale support and single-event based overrides.

Issue #1786490 by Berdir, amateescu, damiankloip, Wim Leers, dawehner: Add caching to the state system.

Revert "Issue #1786490 by Berdir, amateescu, damiankloip, dawehner: Add caching to the state system."

This reverts commit 8ec847cc.

Issue #2019055 by plach, fago, berdir, yched, Gábor Hojtsy, kfritsche, jibran: Switch from field-level language fallback to entity-level language fallback.

Revert "Issue #2019055 by plach, fago, kfritsche: Switch from field-level language fallback to entity-level language fallback."

This reverts commit 46942cd3.

Issue #2019055 by plach, fago, kfritsche: Switch from field-level language fallback to entity-level language fallback.

Issue #2063055 by Gábor Hojtsy: Sync language list with translations (add fy, ga, hy, km, ms and sw).

Issue #1856976 by andypost, Soul88, ACF, aspilicious, vijaycs85, dawehner: Convert language_count() to the state system.

Issue #1833022 by e0ipso, plach, YesCT, kfritsche, penyaskito, vijaycs85, nod_, cam8001: Only display interface language detection options to customize more granularity.

Issue #1754246 by webflo, swentel, penyaskito, andypost, alexpott, YesCT, dagmar: Languages should be configuration entities.

Issue #2020301 by plach, Berdir: Make the $type parameter of LanguageManager::getLanguage() optional.

Issue #1845034 by RobLoach, sandykadam, nick_schuch, cam8001, Gábor Hojtsy: Convert standard.inc to Drupal\Core\Language.

Issue #1888424 by katbailey, steveoliver, twistor, beejeebus, effulgentsia: Change notice: Make Drupal's URL generation logic available to HttpKernel, and minimize code repetition/divergence.

Issue #1620010 by dawehner, ParisLiakos, plach, jibran: Move LANGUAGE constants to the Language class.

Issue #1899994 by katbailey, plach, YesCT: Disentangle language initialization from path resolution.

Passing the request object explicitly to the language negotiation methods instead of a vague args parameter

Using the language_manager wrapper function to return a language whether or not we're in the requet scope