Stewie is a two-year-old prodigy who has a very sophisticated psyche and is able to speak very fluently in an upper-class English accent with quite advanced vocabulary. He reaches his first birthday in the season 1 episode "Chitty Chitty Death Bang", and we see the family celebrate Stewie's birthday in a cutaway gag in the season 12 episode "Chap Stewie". As Stewie's first birthday was celebrated in the episode "Chitty Chitty Death Bang", it is safe to assume that it was Stewie's second birthday in the episode "Chap Stewie". Highly literate and able to cite pop culture references that long predate his birth, Stewie is also entranced by Raffi and "Teletubbies". Stewie succumbs to other childish tendencies; he believes Peter has truly disappeared in a game of Peekaboo, often has difficulties understanding the concept of shapes, talks to his teddy bear Rupert as if he were alive, is overcome with laughter when Lois blows on his stomach; and has no idea how to use a toilet. MacFarlane has stated that Stewie is meant to represent the general helplessness of an infant through the eyes of an adult. Per cartoon physics, his ability to move objects of greater weight than himself is not surprising to other characters, nor is his ability to retrieve firearms from hammerspace or his ability to talk. According to "Don't Be a Dickens at Christmas", he understands German (but cannot speak it), as his mother is of German descent and the Pewterschmidts (except Lois) speak it.