Install xfonts-thai-etl by entering the following commands in the terminal:
sudo apt update sudo apt install xfonts-thai-etl
Description:
Thai etl fonts for X
This package provides 3 Thai TIS-620 monospace (with full-width combining characters) bitmap fonts for X developed by ETL. . Emacs/Mule needs these fonts to display Thai. Only normal weight is provided, though.
Homepage: https://linux.thai.net/projects/thaixfonts
Version: 1:1.2.7-3
Section: universe/x11