Tai Font Vn-uni.shx [best]
Even with the font installed, you might need to adjust the text style: in the command line. Find the text style used in the problematic text. Change the font to Tai Font Vn-uni.shx Summary of Essential Vietnamese AutoCAD Fonts
Taken together, Tai Font Vn-uni.shx reads as a purpose-built, technical-font artifact: a compiled shape/font offering Tai-script glyphs and Vietnamese coverage, prepared for use in environments where conventional font formats (OTF/TTF) are impractical or unsupported. Tai Font Vn-uni.shx
If you want, I can:
Edit the FMP file to include: Tai Font Vn-uni.shx;Arial.ttf Even with the font installed, you might need
When downloading .shx files from the internet, be cautious. Some malicious scripts can be embedded in font files. Always scan the file with an antivirus program before copying it to your system folders. Even with the font installed