waul vs whimper

waul

verb
  • To wail, to cry plaintively. 

whimper

verb
  • To cry or sob softly and intermittently. 

  • To cry with a low, whining, broken voice; to whine; to complain. 

  • To say something in a whimpering manner. 

noun
  • A low intermittent sob. 

How often have the words waul and whimper occurred in a corpus of books? (source: Google Ngram Viewer )