Once you've created resource files for your application, you will need to set the supported cultures for your project. To do so, complete the following steps:

1. In the Solution Explorer, right-click your project and select Unload Project. The project will appear grayed out and unavailable.
2. Right click the project again, and select the Edit ProjectName.csproj option (or Edit ProjectName.vbproj, where ProjectName is the name of your project).        
3. In the .csproj file, locate the <SupportedCultures></SupportedCultures> tags. In between the tags, list the cultures you want to be supported, separating each with a semicolon.        

   For example:

   <SupportedCultures>fr;es;en;it;ru</SupportedCultures>
   

   This will support French, Spanish, English, Italian, and Russian.

4. Save and close the .csproj or .vbproj file.
5. In the Solution Explorer, right-click your project and choose Reload Project from the content menu.

The project will be reloaded and will now support the specified cultures.