If you downloaded an official language pack archive, extract the files and drop the .dat and .fat contents directly into the Far Cry 4\data_win32\ folder. Overwrite any existing files if prompted.
If you have searched for the term , you are likely facing one of three problems: you want to play the game in your native tongue, you want to switch the audio to English from a regional version, or you want to experience the game in a specific language (like French, German, or Russian) to practice your skills.