TYPO3 Core

I have some categories called "Allgemeine Dokumente" and "Unterkategorie" and translated it from german to english.

"Allgemeine Dokumente" -> "General Documents"
"Unterkategorie" -> "Subcategory"

I translated my example page but now the english title will be displayed always.

In my extension I just did something simple:

// PluginController

protected function defaultAction() {
  // Already imported the CategoryRepository class.
  $repository = $this->objectManager->get(CategoryRepository::class);
  $query = $repository->createQuery();
  $settings = $query->getQuerySettings();
  $settings->setRespectSysLanguage(true);
  // Language uid 0 === german, 1 === english
  $settings->setLanguageUid(0);
  $query->setQuerySettings($settings);
  $this->view->assign('categories', $query->execute());
}

Where is the problem? Why I get the "german" record with an english title?!