To get clear voice and add to DTS 5.1

[Granader]

I got Latvian Audio track( 192 Kbps, 2ch )

First I wanna clear any sounds from track, leave only clear translation.
With what effects, softwares, it can be done + - normaly?

And then I will mix cetral channal with that clear sound, and put that central channal to Original DTS 5.1?

If its possiblenbe to make DTS 5.1 like this? Maybe some better ideas?