Hi, and thank you for your interest!
yast-gtk is being translated using Weblate, a web tool designed to ease translating for both developers and translators.
Translation project for yast-gtk into Thai currently contains 267 strings for translation and is 9.7% complete.
If you would like to contribute to translation of yast-gtk, you need to register on this server.
Once you have activated your account just proceed to the translation section.