u vs y'

u

pron

  • you (in text messaging and internet conversations) 

character

  • The twenty-first letter of the English alphabet, called u and written in the Latin script. 

noun

  • The name of the Latin-script letter U/u. 

  • A thing in the shape of the letter U 

y'

pron

  • you; ya; ye. 

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