dog's tongue vs heckle

dog's tongue

noun
  • The plant hound's tongue. 

heckle

noun
  • The long shining feathers on a cock's neck. 

  • An interruption during a show, especially a comedy performance 

  • A feather ornament in the full-dress bonnets of Highland regiments. 

verb
  • To question harshly in an attempt to find or reveal weaknesses. 

  • To insult, tease, make fun of or badger, especially during a comedy performance. 

  • To prepare flax for spinning using special combs called hackles 

How often have the words dog's tongue and heckle occurred in a corpus of books? (source: Google Ngram Viewer )