It sounds like you're asking whether changing the language in ACDSee actually works, or how to do it properly.
System UI: For a complete shift, ensure your Windows Display Language is set correctly in Settings | Time & Language | Language & Region. Language Packs - ACD Systems
Selecting a Language: If multiple languages are already installed, select your preferred one from the dropdown menu and click OK.
Language not available: If the language you want to use is not available in the Language tab, you may need to download a new language pack from the ACDSee website. Follow the instructions on the website to download and install the language pack.
Language not changing: If you've selected a new language but it's not taking effect, try restarting ACDSee. If the issue persists, try uninstalling and reinstalling the software.
Text not translating: If some text is not translating to the new language, it's possible that the translation is incomplete or not available. You can try contacting ACDSee support to report the issue.
Download a multilingual version from ACDSee’s website.
Reinstall and choose a different language during setup.
Check for language packs on their official support page.
, the language is often "locked" to the specific installer you used. Download the Correct Version
Conclusion
: Unlike the Photo Studio, this specific product sometimes includes a dropdown under Edit > Options that allows for easier switching. Help Resources