Install xfonts-thai-manop by entering the following commands in the terminal:
sudo apt update sudo apt install xfonts-thai-manop
Description:
Manop Wongsaisuwan's bitmap fonts for X
This package provides 4 Thai TIS-620 pseudo-monospace (with zero-width combining characters) bitmap fonts for X developed by Dr. Manop Wongsaisuwan while he was in the US. . These fonts are good for xiterm+thai, but with only normal weight provided.
Homepage: https://linux.thai.net/projects/thaixfonts
Version: 1:1.2.7-3
Section: universe/x11