Is there an application for converting digital sound into a Word document?

I am required to transcribe all video clips that are posted on our internal website (for ADA purposes). Transcribing is very time consuming -- I play the video in slow motion a zillion times and type until all of the text is captured. Ugh.

I am looking for an application/utility that will "listen" for the audio in these clips and create a word processing document. Dragon Naturally Speaking will not work because the voices are always different. I keep thinking something has to be out there. Thanks for any suggestions.