Thanks I'll give it a try, but I think I see the difference between your example and how I've configured my lists. My version of list configuration (using you country/language example) would be like this:
Country List:
CA Canada
US United States
MX Mexico
Language List:
English US; CA
French CA;
Spanish US; MX;
In my language list configuration the country code field is a lookup item with the option for selecting multiple values so the data that gets put in the field isn't just a single country code but rather a delimited list of values.
Quite possible that I need to rethink my list configuration.