The font that Composer uses for writing Vietnamese content is very difficult read. We have an entire news group that writes their content in Word because they can use a more readable font like Be Vietnam Pro then paste the content into Composer.
In short, they would rather go through the extra steps to copy and paste than use Composer with the current Vietnamese font. Was the font that was chosen for Composer ever tested with native Vietnamese writers/readers?
Instead, please change the font that Composer uses. Be Vietnam Pro is a Google font and is compatible with Composer.
Hi there! While we understand the pain experienced here with the current font's lack of support for Vietnamese, we don't have immediate plans we can share to address this. We will certainly keep this on our radar especially as we look at scalable support for other languages and appreciate your patience!