There are two methods to switch the language, depending on how your game was installed.
Many versions of Crysis Warhead (e.g., Russian, German, Polish, or Asian localized releases) either lack English voiceover entirely, ship with incomplete English files, or force you to play with translated subtitles and menus. This pack restores the without breaking the game or requiring a full reinstall. Crysis Warhead English Language Pack
How to Install and Change the English Language Pack in Crysis Warhead If you have installed Crysis Warhead There are two methods to switch the language,
The Crysis Warhead English Language Pack offers the following features: ship with incomplete English files
After installing, test the first mission “Call Me Ishmael.” If Psycho’s intro line (“They call me Psycho…”) is in English, the pack worked correctly.