How to Install Thai Language Support on 1.5.1.3.1

I have a English Store but need to add Thai Language support for the surfer side ( not admin ) can one of the Thai speaking users help me with instructions and or source files for language.

I know there is a Siam Webboard but I cannot read Thai so cannot signup and post this question on that site.

PLEASE PM if you can help or reply to this post.

Hi,
Now the Thai language for Opc 15131 don't released on opencart.com but released on opencart2004.com(New team Thailand developer) if u need one please send a pm to me.

Thanks.