Originally Posted by
eversonpoe
have you not watched the "between two worlds" special feature where he sits down and talks to them (and a guy who worked on the series during its original run) and explains why? it's a special feature on both the DVD gold box and the "complete mystery" blu-ray box (it's longer on there). there's also one where he interviews the "palmer family" as their characters, and then talks to them as the actors. both are great and totally worth watching. sadly, i can't seem to find them online.
anyway, kyle is "kale" because of dino delaurentis being unable to pronounce his name while they were making dune, and madchen is "madgekin" because david gave her that nickname for fun. there's more detail than that, but that's the gist of it.