
Much to the bewilderment of the French, the English won a major upset and began mocking the French by waving their middle fingers at the defeated French, saying, "See, we can still pluck yew! PLUCK YEW!"
Since 'pluck yew' is rather difficult to say, the difficult consonant cluster at the beginning has gradually changed to a labiodental fricative 'F', and thus the words often used in conjunction with the one-finger-salute are mistakenly thought to have something to do with an intimate encounter. And since the feathers on the arrows used with the longbow come from pheasants, the symbolic gesture became known as "giving the bird."


