allay vs assuage

allay

verb
  • To make quiet or put at rest; to pacify or appease; to quell; to calm. 

  • To alleviate; to abate; to mitigate. 

noun
  • Alleviation; abatement; check. 

assuage

verb
  • To pacify or soothe (someone). 

  • To lessen the intensity of, to mitigate or relieve (hunger, emotion, pain etc.). 

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