vocalize vs vowelise

vocalize

verb
  • To sing without using words. 

  • To produce noises or calls from the throat. 

  • To add vowel points to a consonantal script (e.g. niqqud in Hebrew) 

  • To express with the voice, to utter. 

  • To turn a consonant into a vowel. 

vowelise

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