Install language-pack-gnome-th-base by entering the following commands in the terminal:
sudo apt update sudo apt install language-pack-gnome-th-base
Description:
GNOME translations for language Thai
Translation data for all supported GNOME packages for: Thai . This package provides the bulk of translation data and is updated only seldom. language-pack-gnome-th provides frequent translation updates, so you should install this as well.
Version: 1:18.04+20180423
Section: translations