My AssemblyInfo contains information about my product, company etc.. this data is currently hard coded in the cs file:
[assembly: AssemblyCompany(\"My Compan
Yes, this is possible. The attributes themselves are very rarely read by humans that would care about the language. They are however also used by the C# compiler to generate a default version of the /win32res compile option.
Which affects what you see when you look at the assembly properties in Explorer, using the Properties shortcut menu item and look at the Details tab. What Windows displays here are not the assembly attributes, it doesn't know anything about managed assemblies. What you see is the data in an unmanaged resource, embedded in the assembly.
You can see what these unmanaged resources look like with Visual Studio. Use File + Open + File and navigate to a sample EXE assembly. You'll get a treeview of the embedded resources, a typical .NET program should have at least three of them. An icon, a manifest that makes the program UAC compatible. And a Version resource, the one you care about. Open that node and you see a resource with ID 1, marked [Neutral]. Neutral is the "works in any language" version of the resource. Double-click it to open the editor (won't work in Express), you can see how the assembly attributes are mapped to Version resource properties.
What you need to do is create your own version of these unmanaged resources, a version that uses more than one language. That requires writing a .rc file, a resource script that then gets compiled into a .res file by the rc.exe tool, the unmanaged resource compiler. You then use Project + Properties, Application tab, "Resource File" radio button to tell the compiler about it.
Do beware that this is bit painful and error prone, rc.exe is a temperamental tool and you do lose the direct link between AssemblyInfo.cs and what you see in Windows, it is a maintenance item. The best way to go about it is to use a dummy C++ project and use its built-in resource editor to put it together.