Why do they dubb in stuff?

I don't see Bust a Move or Two of a crime listed on the episode guide. Anyone know which one I should watch first? I haven't seen any since last summer, I believe. Thanks!

Whenever there are a host of shows, it's not scripted at the time, so they go back in and re-dub what they should be saying. They said Donald Trump was one of the worst ones on The Apprentice. they had to re-dub him all the time.