I don't understand why you would get a compiler warning on that. I'm not getting it with Delphi 10.3.3 and since you are compiling from the source on bitbucket we should be using the exact same compiler options.   This is really strange. You are getting an error when the project default source language is set. The origin of the default value is the GetUserDefaultLCID Win32 API function... but $2000 isn't a valid LCID value. My guess is that you are using a custom locale (see: Locale Names without LCIDs). I had hoped I wouldn't have to deal with those but I guess I weren't that lucky. You can probably work around the problem by modifying the default locale settings in the registry: HKEY_CURRENT_USER\Software\Melander\TranslationManager\System DefaultSourceLanguage=1033 DefaultTargetLanguage=1033 The above values sets them to "English (United States)". I will have to see if I can reproduce the problem here and then figure out how to deal with it. Stay tuned...   There are several ways you can control what language to use at run time. Start by reading the Delphi help topic "Deploying Localized Applications". This explains how you can override the default language choice using the registry. BTM itself can be used as an example of how to load a specific resource module based on a user choice. Look in amTranslationManager.dpr in the function named LoadResourceModule and in amLocale.pas in the function named LoadNewResourceModule. There used to be a Delphi example project (RichEdit or something like it) that demonstrated how to localize an application and how to switch resource modules at run time but I don't think it's been included for a while.