encourage vs slow down

encourage

verb
  • To mentally support; to motivate, give courage, hope or spirit. 

  • To spur on, strongly recommend. 

  • To foster, give help or patronage 

slow down

verb
  • To reduce the velocity, speed, or tempo of something. 

  • To decelerate. 

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