def WordSeries(words, conjunction='and'):
    """Convert a list of words to an English-language word series.

  Args:
    words: A list of word strings.
    conjunction: A coordinating conjunction.

  Returns:
    A single string containing all the words in the list separated by commas,
    the coordinating conjunction, and a serial comma, as appropriate.
  """
    num_words = len(words)
    if num_words == 0:
        return ''
    elif num_words == 1:
        return words[0]
    elif num_words == 2:
        return (' %s ' % conjunction).join(words)
    else:
        return '%s, %s %s' % (', '.join(words[:-1]), conjunction, words[-1])
