task vs undertake

task

verb
  • To assign a task to, or impose a task on. 

  • To charge, as with a fault. 

  • To oppress with severe or excessive burdens; to tax 

noun
  • Any piece of work done. 

  • A difficult or tedious undertaking. 

  • A process or execution of a program. 

  • An objective. 

  • A piece of work done as part of one’s duties. 

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 task and undertake occurred in a corpus of books? (source: Google Ngram Viewer )