[K12OSN] Prevent default language change

[Hung Phan]

We setup a generic account for general computer usage in our lab. A  
student changed the language to Hebrew and set it to be the default.  
As the result, all systems login after that have the Hebrew language  
set. A few mouse click and we can change it back but how do we set to  
prevent the student from ever change the language?
Are any others prevention that you do with your K12LTSP?

Thank you,