I love this game like most of hardcore stalker series fans, but I don't like the English voices with the silly accents, so lets change it to same level like Shadow of Chernobyl was - English text and Russian voices

There is a way to replace English voice-over vocals with original Russian vocals in same time by keeping English text including subtitles in game

Steam SteamApps common Stalker Call of Pripyat gamedata. It's up to you whether you copy the entire configs folder into your gamedata folder and delete. For S.T.A.L.K.E.R.: Call of Pripyat on the PC, a GameFAQs message board topic titled 'Getting Original Gamedata Files'. S.T.A.L.K.E.R.: Call of Pripyat is the third third stand-alone game in the highly-acclaimed survival FPS S.T.A.L.K.E.R. Arsenal Overhaul is a full weapons conversion for S.T.A.L.K.E.R Call of Pripyat 1.6.02. It features over a 100 new weapons, 28 new ammunition types and 6 new suits. All vanilla weapon models have been replaced with high quality versions. All weapon sounds have been replaced with new original sounds and more variation in stalker NPC's. Continue browsing in r/stalker r/stalker All about the S.T.A.L.K.E.R. Survival-horror computer game series (including Shadow of Chernobyl, Clear Sky, Call of Pripyat, and community mods for each).

Download ENGLISH text with RUSSIAN Vocals FIX from here: Stalker COP: ENGLISH text/RUSSIAN Vocals

Few notes how to successfully apply this FIX: (These same notes are also included in self-extracting archive welcome message)
EXTRACT gamedata to root of COP folder, self-extracting archive will do it for you if you don't have problems with installation directory path, Proceed with 'install'
DELETE english.db from localization folder, DONE, launch the game!
* IFChanges somehow didn't take effect and game has still childish
English vocals then game main config file has to be modified manually:
EDIT 'gamedata' line (9th from the top) in fsgame.ltx file (use notepad

Stalker Cop Gamedata Folder

to edit, file is located in COP main root) - as both values 'true' like

Stalker Call Of Pripyat Gamedata Folder Locker Box

shown below:

Stalker Gamedata Folder

Gamedata Folder