Here’s a review based on the typical role of the Sound-english.dat and Sound-english.fat files in : Review: Far Cry 3 – Sound-english.dat & Sound-english.fat Files Purpose: These two files ( Sound-english.dat and Sound-english.fat ) contain the majority of the game’s English voice acting, mission dialogue, radio chatter, enemy callouts, and certain ambient sound cues. The .fat file is an index (table of contents), while the .dat holds the actual audio data.