 CHAR: The spelling of "ize" words turns out to be an important plot  point and it seems that Mayo regards the spelling of words like  "realize" with a "z" as being somehow inferior. As a linguistic  pedant (he makes a good deal of fuss about words and their use  throughout the episode), he would be aware that although "realise"  is the more common modern UK spelling, genuine British pedants  favour "realize" and dont dismiss it as a vulgar Americanization,  but view it instead as the "proper" way to spell such words.