So, okay.
(I did it that way)
I got offsets form "Clasic wow 1.12 5875"
So I start to see how the addresses are stored, where are stored.
From "5875" to "5.1.0 16357" It was easy to find out and match them. (It take me 2 days LoL )
But after that I found that (I'm big noob at that ):
The offsets for 'lang' is placed only at audioLocale (I named the addres "GetLocaleClient" is the offset who i need) http://imgur.com/a/XH0Yd
You have to play some time with IDA to understand it.
It's easy just do it.
PS. See in old client where is those and than Try in actual version.
Have fun : http://pastebin.com/NJYgw8h4