If you switch from English to another language and then back, Steam will re-download the English files. This actually fixes many corrupted text issues.
Empire Total War stuck in a different language. : r/totalwar empire total war language settings better
Choose your desired language from the dropdown menu. If you switch from English to another language
If the Steam method fails, or if you want to force a specific language via the game's script files: empire total war language settings better
If the game refuses to switch, it may be following your Windows "System Locale" for non-Unicode programs. Steam Community How do I change the language on my Empire Total War