Language segregation

Hi all,
I'm trying to alter the following script, which currently checks the users browser language settings & then re-directs American-English users to american.html & others [including English (UK)] to english.html
<script LANGUAGE="JavaScript1.2">
-1) document.location.href = 'american.html';
else
document.location.href = 'english.html';
// End -->
</script>

What I would like to do (if possible) is to check the language setting of the users keyboard.
This is far more accurate as English (UK) users often leave the browser language set at the default (en-us) but need to change the keyboard settings to make the £ sign.

I’ve tried changing var language = navigator.browserLanguage;
to var language = navigator.keyboardLanguage;
as you would if you wanted to change to var language = navigator.userLanguage; or something
but I get a “ ‘language’ is not an object” error.

Is it possible to check the keyboard setting ?

Any help appreciated.

Hugh