public static TranslateOption sourceLanguage(String sourceLanguage) {
      return new TranslateOption(TranslateRpc.Option.SOURCE_LANGUAGE, sourceLanguage);
    }
Returns an option for setting the source language. If not provided, Google Translation will
try to detect the language of the text to translate.

@param sourceLanguage the source language code
java-translate/google-cloud-translate/src/main/java/com/google/cloud/translate/Translate.java