A silly telephone joke

I remember this joke told to me when I was a kid by my brother-in-law. It helps, but isn't essential, to know that the surname 葉 (or simplified 叶), is Yap in Hakka and Hokkien, Yip in Cantonese (and Ye in Mandarin).

A: Hello, is that Yip?
B: Yup!
A: Yap?
B: Yip!
A: Sorry?
B: Y.I.P!
A: I don't know why you pee.

 

I would like to call a wrong number, please