blueskirt42: I don't believe there is such a thing unfortunately. Four years ago, when I got that copy of the Jagged Alliance 1 strategy guide on ebay, I got into a Jagged Alliance 1 and Deadly Games mood, and for several months I replayed both games, collecting data, figuring out secrets, writing pages on the Jagged Alliance wikia and trying for the longest time to figure out how some stats works, but I didn't come across any voice extractor for the game, which would have come in handy because I had to design a bunch of crash courses in the map editor of Deadly Games to put the mercs into as many situations as possible to hear as much unique lines as possible to update some pages on the wikia.

The only modding program I found was the Merc Editor program which, prior to the release of Deadly Games v1.13, could be used to read and edit the stats of the mercenaries and a few hidden values (like their trait, hair/skin colors, body shapes and who they liked/hated.)

With the release of Deadly Games v1.13, Sir-Tech (to prevent players from cheating and breaking their games) added one additional bit of blank data to every mercenary, which messed with the Merc Editor and made it unusable (you could edit the first merc without a problem, but when you checked the second merc, instead of reading the name of the second merc, it reads the bit of blank data from the first merc, and then instead of reading the strength of the second merc, it reads the name of the second merc, and instead of reading the dexterity of the second merc, it reads its strength... and since the program expected to read an integer but is fed a string instead, it displayed garbled text.) I recall installing v1.08 from a CD, to get the old merc data file and then comparing the one supplied with v1.13 with the one supplied in v1.08 in a hex editor to find out what was wrong with the new one before spotting that extra bit of blank data every now and then at a regular interval.

But yeah, thanks to the Baldur's Gates Syndrome, the modding community completely skipped the first game in favor of Jagged Alliance 2, so you'll hardly find any modder interested in tweaking around with the first generation of Jagged Alliance games. Which is a shame because there are still a bunch of unexplained values and data in the early games that haven't been explained yet, and because an open source version of JA1 with modding capabilities, similar to OpenXcom, would be so sweet.

ZFR: I have the CD version of the game and wanted to hear all mercenary voices. I remember long ago (in the 90s) I came across a FAQ with this info:

(38) I don't want to try out all mercs but I would like to hear their
voices. How do I get it ?
A: Information provide by Carsten Engelmann:

On the CDROM are all the sound files. They are mostly 11kHz,
stereo and 8bit. The format is probably VOC. They can be played
with Mediavision's playfile.exe.
Look for the file e.g. 'nat' and play it with playfile.exe or
'vplay -S -s11' under Linux. It's the collection of Elio's sayings.
Other mercs have numbers. E.g. Bud has 11, Reuben has 20. I don't
have a Soundbalster so I don't know the tools but it's probably the
'voc'.

Not sure how the GOG version looks like, but it's something you could try.
https://www.gamefaqs.com/pc/565057-jagged-alliance/faqs/2091