stutter vs vowelize

stutter

verb
  • To speak with a spasmodic repetition of vocal sounds. 

  • To exhaust a gas with difficulty 

noun
  • A speech disorder characterised by stuttering. 

vowelize

verb
  • To give the quality, sound, or office of a vowel to. 

  • To insert a vowel or vowels into. 

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