Concrete implementation may throw an UnsupportedTranslationMethodException if particular method is not available / implemented.
 /**
  * Returns translated string found under the $labelId.
  *
  * Searches for a translation in the source as defined by $sourceName
  * (interpretation depends on concrete translation provider used).
  *
  * If any arguments are provided in the $arguments array, they will be inserted
  * to the translated string (in place of corresponding placeholders, with
  * format defined by these placeholders).
  *
  * If $quantity is provided, correct plural form for provided $locale will
  * be chosen and used to choose correct translation variant.
  *
  * @param string $labelId Key to use for finding translation
  * @param array $arguments An array of values to replace placeholders with
  * @param mixed $quantity A number to find plural form for (float or int), NULL to not use plural forms
  * @param Locale $locale Locale to use (NULL for default one)
  * @param string $sourceName Name of file with translations, base path is $packageKey/Resources/Private/Locale/Translations/
  * @param string $packageKey Key of the package containing the source file
  * @return string Translated message or NULL on failure
  * @api
  * @see Translator::translateByOriginalLabel()
  */
 public function translateById($labelId, array $arguments = [], $quantity = null, Locale $locale = null, $sourceName = 'Main', $packageKey = 'Neos.Flow')
 {
     if ($locale === null) {
         $locale = $this->localizationService->getConfiguration()->getCurrentLocale();
     }
     $pluralForm = $this->getPluralForm($quantity, $locale);
     $translatedMessage = $this->translationProvider->getTranslationById($labelId, $locale, $pluralForm, $sourceName, $packageKey);
     if ($translatedMessage === false) {
         return null;
     }
     if (!empty($arguments)) {
         return $this->formatResolver->resolvePlaceholders($translatedMessage, $arguments, $locale);
     }
     return $translatedMessage;
 }