if you just put language file in your fone it wont work, you shoul do in this way: for example you want to have english in your fone and you have uk.lng
rename it into file of language that already exists in your phone (french for example), i meen uk.lng -> fr.lng and replace it, but remember it bugs on sms and also may bugs anywhere else!!! want to have no bugs - flash with fs of the same version of sw and customize it with correspondence custom pack!!!
good luck!!!