installLanguageOverrides example

// Update URL Prefixes for all languages after the     // LanguageManagerInterface::getLanguages() cache is flushed.     language_negotiation_url_prefixes_update();

    // If after adding this language the site will become multilingual, we need     // to rebuild language services.     if (!$this->preSaveMultilingual && !$update && $language_manager instanceof ConfigurableLanguageManagerInterface) {
      $language_manager::rebuildServices();
    }
    if (!$update) {
      // Install any available language configuration overrides for the language.       \Drupal::service('language.config_factory_override')->installLanguageOverrides($this->id());
    }

    if (!$this->isLocked() && !$update) {
      // Add language to the list of language domains.       $config = \Drupal::configFactory()->getEditable('language.negotiation');
      $domains = $config->get('url.domains');
      $domains[$this->id()] = '';
      $config->set('url.domains', $domains)->save(TRUE);
    }
  }