sing out vs ululate

sing out

verb
  • To call out; yell. 

  • To start singing. 

  • To cry out in pain. 

ululate

verb
  • to howl loudly or prolongedly in lamentation or joy 

  • to produce a rapid and prolonged series of sharp noises with one's voice. 

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