shoot one's mouth off vs yak

shoot one's mouth off

verb
  • To make reckless or exaggerated statements. 

yak

verb
  • To talk, particularly informally but persistently; to chatter or prattle. 

  • To vomit, usually as a result of excessive alcohol consumption. 

noun
  • An ox-like mammal native to the Himalayas, Mongolia, Burma, and Tibet with dark, long, and silky hair, a horse-like tail, and a full, bushy mane. 

  • A talk, particular an informal talk; chattering; gossip. 

  • A laugh. 

  • Vomit. 

  • A kayak. 

How often have the words shoot one's mouth off and yak occurred in a corpus of books? (source: Google Ngram Viewer )