chirl vs shrill

chirl

verb
  • To emit a low sound; to warble. 

noun
  • A kind of musical warble. 

shrill

verb
  • To make a shrill noise. 

adj
  • Sharp or keen to the senses. 

  • Having a shrill voice. 

  • Fierce, loud, strident. 

  • High-pitched and piercing. 

noun
  • A shrill sound. 

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