Yes. If you do not want to hunt for a third-party language pack, most digital storefronts allow you to change the language natively without re-downloading the entire game.
The Thief series has undergone several games and remakes, and each iteration would have required its own English language pack. The most recent game in the series, Thief (2014), and its DLCs were localized into multiple languages, including English. Thief english language pack
Please clarify your exact request using one of the following: The most recent game in the series, Thief
If you are a developer wanting to add English to an existing app and call it "Thief Language Pack," then this is a project report. Select Properties > Language
Depending on your platform or version, the "English Pack" is usually applied in one of two ways: : Right-click the game in your Library . Select Properties > Language .
If the Steam toggle fails, players sometimes resort to downloading a "Thief 2014 English Language Pack." This usually consists of a set of .upk files (Unreal Packages) that contain the audio banks. These must be placed in the ThiefGame\CookedPC directory. Note: Exercise extreme caution when downloading .dll or executable files claiming to be language packs; legitimate language packs are usually raw data files, not .exe installers.