constate vs croon

constate

verb
  • To ascertain; to verify; to establish; to prove. 

  • To relay information in a statement and say whether it is true or false. 

croon

verb
  • To say softly or gently 

  • To make a continuous hollow moan, as cattle do when in pain. 

  • To hum or sing softly or in a sentimental manner. 

  • To soothe by singing softly. 

noun
  • A soft or sentimental hum or song. 

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