Is there a way to add English subtitles for S.T.A.L.K.E.R.: Call of Pripyat?

This well-received English translation of the mod 'Winter of Death: Ultimatum', has English subtitles. Since I do not own the game I cannot test them myself, but in the folder gamedata/configs/text/eng/, I found English dialogue files (such as st_dialog_jupiter.xml).

I presume you can install the Russian version of S.T.A.L.K.E.R.: Call of Pripyat via Steam, and copy the contents of the aforementioned folder of this mod to the /text/ folder of the game.

Note however, since they come in a folder specifically named after the language ('eng'), that the Russian version might have its text in gamedata/configs/text/rus, so you might need to replace the files in there (make sure to back them up first, since Steam's Verify Integrity of Game Files might not be able to differentiate between all of them).
An alternative could be editing the localization.ltx file in gamedata/configs/:

[string_table]
language = eng

The last line in all probability reads language = rus and needs to be switched with this.

Please let me know if this helps.