9 files declare their use of LanguageManager

AliasManager.php in drupal/core/lib/Drupal/Core/Path/AliasManager.php: Contains Drupal\Core\Path\AliasManager.
Date.php in drupal/core/lib/Drupal/Core/Datetime/Date.php: Contains \Drupal\Component\Datetime\Date.
FinishResponseSubscriber.php in drupal/core/lib/Drupal/Core/EventSubscriber/FinishResponseSubscriber.php: Definition of Drupal\Core\EventSubscriber\FinishResponseSubscriber.
install.core.inc in drupal/core/includes/install.core.inc: API functions for installing Drupal.
language.admin.inc in drupal/core/modules/language/language.admin.inc: Administration functions for language.module.
LanguageRequestSubscriber.php in drupal/core/lib/Drupal/Core/EventSubscriber/LanguageRequestSubscriber.php: Contains \Drupal\Core\EventSubscriber\LanguageRequestSubscriber.
LanguageTestManager.php in drupal/core/modules/language/tests/language_test/lib/Drupal/language_test/LanguageTestManager.php: Contains \Drupal\language_test\LanguageTestManager.
LocaleConfigSubscriber.php in drupal/core/modules/locale/lib/Drupal/locale/LocaleConfigSubscriber.php: Contains \Drupal\locale\LocaleConfigSubscriber.
PathProcessorLanguage.php in drupal/core/modules/language/lib/Drupal/language/HttpKernel/PathProcessorLanguage.php: Contains Drupal\language\HttpKernel\PathProcessorLanguage.