[TICI]

You need to install the DGEN Patch Enjoy Patch for NoAddons V. 5.2 . this way you will see the briefing in english but the pilot ranks still will be in russian for the RAF pilots. Remember that there are different patches for the Dgen according to the type of game installation you have . If you installed the game out of box up to HSFX 5.0 or 5.01 that's the patch you need . The patch I believe is on Mission 4Today downloads.
Make sure to disable all the mods before you patch.
TICI