The entire story/plot, dialog, characters, graphics, movies and engine were created by BioWare, here in Edmonton. One reason the 4000 years before the movies setting was chosen was to have the artistic freedom of coming up with an original story in an established universe.
Sound was supplied by LucasArts from their awesome sound archive, implementation was done by Bioware. Music was composed by Jeremy Soule (
http://www.lucasarts.com/products/swkotor/GI_music.html), Voice Acting by several highly talented people (
http://www.lucasarts.com/products/swkotor/GI_voice.html)All in all the credits of the game sum it up pretty well.
Hope that clears things up.
georg at bioware dot com
This comment was edited on Mar 27, 18:46.