embark vs undertake

embark

verb
  • To start, begin. 

  • To cause to go on board a vessel or boat; to put on shipboard. 

  • To get on a boat or ship or (outside the USA) an aeroplane. 

  • To engage, enlist, or invest (as persons, money, etc.) in any affair. 

undertake

verb
  • To take upon oneself; to start, to embark on (a specific task etc.). 

  • To commit oneself (to an obligation, activity etc.). 

  • To pass a slower moving vehicle on the curbside rather than on the side closest to oncoming traffic. 

noun
  • The passing of slower traffic on the curbside rather than on the side closest to oncoming traffic. 

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