The language he was speaking is called "Ubby Dubby". It was spoken on the PBS show "Zoom" back in the 1970's. To speak Ubby Dubby, insert the letter "b" into all syllables of every word. Aichu doesn't know what he is talking about. For example, "Hebelebo, myby nabame ibis Libisaba, whabat ibis yobour nabame?" is "Hello, my name is Lisa, what is your name?"
The King of Queens is a TV series directed by John Fortenberry which has been on air since 1998. The Mentalo case is the 11th episode from the 5th season that was put on air in December 2002. Spence's friend was nostalgic about his childhood and was only using the baby language.You can know in detail about this episode at the link below: