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])