His face went from red to green faster than a set of traffic lights. And it didn't stop there. Within seconds it was the grayish white of old porridge. " P-P-Petunia! " he gasped.
For example, after 6th century, German words starting with P, systematically shifted to a PF sound, while the Old English counterparts kept the P unchanged.
" But you won't talk to me! P—perhaps it would be best if we just...just p—paid and you went and met up with Hermione G—Granger, like you obviously want to! "