I have a foreign instructional DVD and I would like to change its source audio in order to put English voice-overs on it. Is this possible, and if so, how would I go about doing this, please?

I also need software that would allow me to rip specific chapters from a DVD and turn them into files that I can burn onto a new DVD to create an movie with only those isolated chapters as opposed to all of the chapters.

The scenario is such that I have a DVD on learning on a foreign language and I only need certain unit sections on the DVD, and I also need to modify the audio on these sections for implementing voice translations. This way I can create a whole new DVD-CD that only has the units I need with the audio I want.

Thank you for your help.

I don't think we're allowed to discuss this.

Why? What I'm doing is perfectly legal. I own the rights to the DVD and its content as a subscriber and instructor of foreign language education. I'm asking for legit software I can purchase to do what I need it to do. Thanks.

http://forum.dvdtalk.com/showthread.php?t=401647

Owning the DVD doesn't mean you have the right to break its encryption according to the DMCA. There may be an exclusion from that prohibition in the DMCA for educational purposes, but that exclusion doesn't mean we'll discuss the subject here.