guest account & language hot keys

>New computer
>Installed vista ultimate 64 bit
>enabled guest account with a password
>
>when guest logs in he's unable to switch a language.
>I've discovered that the language hot key is set to none
>and can't be assigned.
>
>I'm talking about control panel -> 'clock, language and region' -> 'change
>keyboards or other input methods' -> 'change keyboards' under the 'keyboards
>and languages' tab -> advanced key settings
>
>'hot keys for input languages'
>action:
>'between input languages'
>under the guest account when assigning the default or any other key and
>clicking apply the the setting is resets to none
>
>giving the guest account user or administrator privilages doesn't effect the
>problem
>creating a new account works fine as it is without any settings changes.
>
>can anyone check or verify the problem?