When I worked onto my SW project, I used four laserdisc soundtracks (plus one VHS HiFi stereo); of the LD ones, two were "right", while the others had some problems (really can't remember which kind). So, at the end, I had two couples of similar soundtracks that could be used to extract the dialogues (one couple right, one couple wrong)...

So, it is possible to use, let's say, the english and french soundtrack (or german and spanish) if they match all except the dialogues? If so, how? Can I use Audacity to do that? At the end, as "side effect", it could be also possible to extract the isolated score, right?