"if I know the letters"
Wordplay
Act 1,
Scene 2
Lines 61-64
Servant
Romeo
Servant
Romeo
In his response to the servant, Romeo means "Yes, I can read in a language that I know." But the servant thinks that he doesn't "know his letters," that is, that he can't read. So he starts to go on his way until Romeo calls him back, assuring him that he can read.