Say, if typ file is using unicode, it is possible to know which language any character belongs to.
Then can typst provide a method to set different font for different language.

The code seems does not work even for texts explicitly specified language:

#show text.where(lang: "zh"): text.with(font: "Hiragino Sans GB",  size: 6pt)
#text(lang: "zh")[ 汉语 ]