Recently I've do some work on a WPF app which required to support multiple languages in the UI - a spike to see how easy supporting multiple languages is in WPF, the test UI is shown below in English & French: The app is easy enough to understand - change the UI language and all the text based values are updated with the locale specific instances. I wanted to follow the standard pattern of using language specific resource files to store the translated text, these were placed in the standard location inside the project structure: One of the big advantages of using this mechanism is the resources are compiled into a class which can be used in your ViewModels and Views and this is why see above the 'Resource.resx' file - this contains the 'untranslated' resource strings etc: I've been aware for a long time there are 2 culturing settings per thread in .Net - Thread.CurrentCulture & Thread.CurrentUICulture , the second is the one of interest here...