If your game is not in English, first check the built-in settings: Launcher Menu:
Summary
Which are you on (Steam, GOG, or a physical console)? What region is your copy from (e.g., Japan/Asia, Russia)? Resident Evil 5 English Language Patch Download
Resident Evil 5 English Language Patch & Configuration Guide For players encountering Resident Evil 5 If your game is not in English, first
If you can tell me which platform or specific version you have (e.g., “GFWL retail Japanese DVD”), I can give more targeted advice. “GFWL retail Japanese DVD”)
In the top-left (or top-right) corner of this launcher window, click the before clicking "Start Game" Unofficial Language & QoL Patches
When you first launch the game, a window should appear asking you to choose between DirectX 10