assert vs voice

assert

verb
  • To declare with assurance or plainly and strongly; to state positively. 

  • He would often assert that there was life on other planets. 

  • To maintain or defend, as a cause or a claim, by words or measures; to vindicate a claim or title to 

  • To insist on the legitimacy of one's rights, opinion, etc; not to allow oneself to be dismissed; to ensure that one is taken into consideration; to make oneself respected; to be assertive. 

  • To use or exercise and thereby prove the existence of. 

  • To set a signal on a line using a voltage or electric current. 

  • To specify that a condition or expression is true at a certain point in the code. 

noun
  • an assertion; a section of source code which tests whether an expected condition is true. 

voice

verb
  • To give utterance or expression to; to utter; to publish; to announce 

  • To assign the voice flag to a user on IRC, permitting them to send messages to the channel. 

  • To act as a voice actor to portray a character. 

  • To fit for producing the proper sounds; to regulate the tone of 

  • To utter audibly, with tone and not just breath. 

noun
  • Sound uttered by the mouth, especially by human beings in speech or song; sound thus uttered considered as possessing some special quality or character 

  • The tone or sound emitted by an object 

  • That which is communicated; message; meaning. 

  • Sound made through vibration of the vocal cords; sonant, or intonated, utterance; tone; — distinguished from mere breath sound as heard in whispering and voiceless consonants. 

  • An expressed opinion, choice, will, desire, or wish; the right or ability to make such expression or to have it considered 

  • A particular style or way of writing that expresses a certain tone or feeling. 

  • A particular way of inflecting or conjugating verbs, or a particular form of a verb, by means of which is indicated the relation of the subject of the verb to the action which the verb expresses. 

  • In harmony, an independent vocal or instrumental part in a piece of composition. 

  • A flag associated with a user on a channel, determining whether or not they can send messages to the channel. 

  • One who speaks; a speaker. 

  • The faculty or power of utterance 

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