Code Reference Map

When to Use

When exploring core translation code, understanding architecture, or debugging translation issues.

Core Modules

Language — core/modules/language/ - Language entity, negotiation, language types - Key files: - language.api.php — hooks documentation - language.services.yml — DI services - src/LanguageNegotiator.php — negotiation logic - src/Plugin/LanguageNegotiation/ — negotiation method plugins

Locale — core/modules/locale/ - Interface translation, .po files, string storage - Key files: - locale.api.php — hooks documentation - src/LocaleTranslation.php — translation service - src/StringStorageInterface.php — translation string storage

Content Translation — core/modules/content_translation/ - Entity translation, field translatability - Key files: - src/ContentTranslationHandler.php — translation handler - src/ContentTranslationManager.php — manager service - src/ContentTranslationMetadataWrapper.php — translation metadata - content_translation.admin.inc — field sync UI (deprecated 11.4.0)

Config Translation — core/modules/config_translation/ - Configuration translation, schema-based discovery - Key files: - src/ConfigMapperManager.php — discovers translatable config - src/ConfigEntityMapper.php — config entity translation - src/ConfigNamesMapper.php — simple config translation

Core Services

// Language manager
$language_manager = \Drupal::languageManager();
$current_language = $language_manager->getCurrentLanguage();
$default_language = $language_manager->getDefaultLanguage();
$languages = $language_manager->getLanguages();

// Language negotiator
$negotiator = \Drupal::service('language_negotiator');

// String translation
$translation = \Drupal::service('string_translation');
$translated = $translation->translate('Hello');

// Content translation manager
$ct_manager = \Drupal::service('content_translation.manager');
$handler = $ct_manager->getTranslationHandler('node');

// Config translation mapper manager
$mapper_manager = \Drupal::service('plugin.manager.config_translation.mapper');

Entity Translation API

File: core/lib/Drupal/Core/Entity/ContentEntityBase.php

// Key methods (line numbers approximate)
addTranslation($langcode, $values)      // Line ~997
getTranslation($langcode)               // Line ~893
hasTranslation($langcode)               // Line ~980
removeTranslation($langcode)            // Line ~1018
getTranslationLanguages()               // Line ~1057
isTranslatable()                        // Line ~878

TranslatableMarkup API

File: core/lib/Drupal/Core/StringTranslation/TranslatableMarkup.php

// Constructor
__construct($string, array $arguments = [], array $options = [], TranslationInterface $string_translation = NULL)

// Options array keys:
// - 'langcode': Target language
// - 'context': Translation context for disambiguation

Language Negotiation Plugins

Directory: core/modules/language/src/Plugin/LanguageNegotiation/

LanguageNegotiationUrl.php — URL (prefix or domain)
LanguageNegotiationSession.php — Session/query parameter
LanguageNegotiationUI.php — User preference
LanguageNegotiationBrowser.php — Accept-Language header
LanguageNegotiationSelected.php — Default language

Config Schema Paths

core/modules/language/config/schema/language.schema.yml
core/modules/content_translation/config/schema/content_translation.schema.yml
core/modules/config_translation/config/schema/config_translation.schema.yml

Hooks

Language module hooks — language.api.php: - hook_language_types_info() — define custom language types - hook_language_types_info_alter() — alter language types - hook_language_negotiation_info_alter() — alter negotiation methods - hook_language_fallback_candidates_alter() — alter fallback languages

Locale module hooks — locale.api.php: - hook_locale_translation_projects_alter() — alter translation projects

TMGMT (Contrib)

Module: modules/contrib/tmgmt/

src/Entity/Job.php — translation job entity
src/Entity/JobItem.php — job item (content to translate)
src/TranslatorPluginInterface.php — translator plugin interface
src/SourcePluginInterface.php — translation source plugin

Key services:

// Job queue
$job_queue = \Drupal::service('tmgmt.job_queue');

// Source manager
$source_manager = \Drupal::service('plugin.manager.tmgmt.source');

// Translator manager
$translator_manager = \Drupal::service('plugin.manager.tmgmt.translator');

Debugging Helpers

// Check current language context
$interface_lang = \Drupal::languageManager()->getCurrentLanguage(LanguageInterface::TYPE_INTERFACE)->getId();
$content_lang = \Drupal::languageManager()->getCurrentLanguage(LanguageInterface::TYPE_CONTENT)->getId();
$url_lang = \Drupal::languageManager()->getCurrentLanguage(LanguageInterface::TYPE_URL)->getId();

// Dump negotiation methods and weights
$negotiation_info = \Drupal::service('language_negotiator')->getNegotiationMethods();
var_dump($negotiation_info);

// Check if entity is translatable
$entity_type = \Drupal::entityTypeManager()->getDefinition('node');
var_dump($entity_type->isTranslatable()); // TRUE

// Check field translatability
$field = FieldConfig::load('node.article.body');
var_dump($field->isTranslatable()); // TRUE or FALSE