docs: def list_language_models(self, language=None, **kwargs):
          """
          List custom language models.
  
          Lists information about all custom language models that are owned by an instance
          of the service. Use the `language` parameter to see all custom language models for
          the specified language. Omit the parameter to see all custom language models for
          all languages. You must use credentials for the instance of the service that owns
          a model to list information about it.
          **See also:** [Listing custom language
          models](https://cloud.ibm.com/docs/services/speech-to-text/language-models.html#listModels-language).
  
          :param str language: The identifier of the language for which custom language or
          custom acoustic models are to be returned (for example, `en-US`). Omit the
          parameter to see all custom language or custom acoustic models that are owned by
          the requesting credentials.
          :param dict headers: A `dict` containing the request headers
          :return: A `DetailedResponse` containing the result, headers and HTTP status code.
          :rtype: DetailedResponse
          """
  
          headers = {}
          if 'headers' in kwargs:
              headers.update(kwargs.get('headers'))
          sdk_headers = get_sdk_headers('speech_to_text', 'V1',
                                        'list_language_models')
          headers.update(sdk_headers)
  
          params = {'language': language}
  
          url = '/v1/customizations'
          response = self.request(
              method='GET',
              url=url,
              headers=headers,
              params=params,
              accept_json=True)
          return response