In Shakespeare's First Folio (please see the picture), I found that a letter 'u' is used instead of 'v'. For example, "seuen" means "seven". To know this reason, I visited many websites, but what I've got is only the fact that
Before the use of the letter U, the shape V stood for both the vowel U and the consonant V. If you follow this rule, I think "seven" remains "seven" but "you" becomes "yov". Why in the folio is 'u' used as a substitution for 'v'?
I don't either know the reason why 'c' in "Acts" looks like an ampersand '&'.
(It is also strange that 's' in "stage" looks like 'f', but I know it is so-called a long s.)
(picture from https://en.wikipedia.org/wiki/All_the_world%27s_a_stage)