how to constrain picklist values based on the user's locale

Hi All,

I am trying to contrain a pciklist field value based on the user's locale. I have created a custom picklist field and added the locale code in the picklist values. I have also added a "Default" as "Locale()". Then i created a cascaded picklist where the new custom field is parent and the child is the picklist field where i am trying to apply contrain. It works correctly for user of locale "ENG" and the custom field get pre-defaulted correctly but when i login as user with locale as "English-American" i.e. locale code "ENU", it doesn't get predefaulted. Please advise.