predict vs speculate

predict

verb
  • To make a prediction: to forecast, foretell, or estimate a future event on the basis of knowledge and reasoning; to prophesy a future event on the basis of mystical knowledge or power. 

  • To make predictions. 

  • To imply. 

  • To direct a ranged weapon against a target by means of a predictor. 

speculate

verb
  • To make an inference based on inconclusive evidence; to surmise or conjecture. 

  • To make a risky trade in the hope of making a profit; to venture or gamble. 

  • To anticipate which branch of code will be chosen and execute it in advance. 

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