Chinese text in English scrbook with luatexja-fontspec and polyglossia

Question

I have the following document:

\documentclass[12pt,a4paper,oneside]{scrbook}
\usepackage{fontspec}
\makeatletter
\usepackage{csquotes}
\usepackage{luacode}
%\usepackage[UTF8]{ctex}
\usepackage{luatexja-fontspec}
\usepackage{polyglossia}
\setdefaultlanguage[variant=american]{english}
%\setotherlanguage{chinese}
\usepackage{xstring}
\defaultfontfeatures{Mapping=tex-text}
\newfontfamily\chinesefont[Path=/usr/share/fonts/arphicfonts/]{UMing}

\makeatother

\begin{document}

The common transliteration of 易经 is {\enquote{I Ching,}} 
following the now-obsolete Wade-Giles system: modern Romanization 
of almost all modern Chinese texts follows the Hanyu Pinyin standard used here. 
See [huang].

\end{document}

When I try to typeset it, the second Chinese character does not typeset correctly (I get a box with an X in it). This is not the only instance where a character fails to be typeset corretcly. If I uncomment the line for ctex, the Chinese renders correctly, but all the English is typeset wrong. As far as I know, polyglossia does not support Chinese. I have a large document with a lot of brief snippets of Chinese and Japanese text, but the main document language is English (other languages include polytonic Greek, French, Latin, Italian, Russian, and, uh … "voynich"). I was told that lualatex was better at typesetting multiple languages, but I can't get this to work. Suggestions?

Answer 1

If you add \tracinglostchars=2 to your preamble (or search the .log file), you’ll see the warning message,

Missing character: There is no 经 (U+7ECF)
in font file:HaranoAjiMincho-Regular.otf:jfm=ujis!

This comes from trying to use polyglossia commands with luatexja-fontspec. You wanted to set \chinesefont to UMing. However, lualatex-ja does not use \chinesefont, and you don’t tag the text as Chinese for Polyglossia. So, you get the default font from luatexja-fontspec. This is a Japanese font, so it contains only those Chinese characters that happen to share codepoints with kanji.

There are multiple ways to resolve this. If you want to use luatexja-fontspec, you should use its commands to select the CJK font, \setmainjfont, \newjfontfamily, etc. Also set an English text if you don’t want a package overriding the defaults.

Your TeX installation should also be able to find any font in a subdirectory of \usr\share\fonts\ without a Path= argument. I recommend against putting an absolute Path= in your document, since this will give you a document that will not compile on any other computer. Also, there are multiple font faces in uming.ttc, and you should specify which you want.

\documentclass[12pt,a4paper,oneside]{scrbook}
\tracinglostchars=2
\usepackage[match]{luatexja-fontspec}
\usepackage{polyglossia}
\setdefaultlanguage[variant=american]{english}
\usepackage{csquotes}
%\setotherlanguage{chinese}
\usepackage{xstring}

\defaultfontfeatures{ Ligatures=TeX,
                      Scale=MatchUppercase }

\setmainfont{Latin Modern Roman}[Scale=1.0]
\setmainjfont{AR PL UMing TW}[Renderer=HarfBuzz]

\begin{document}

The common transliteration of 易经 is {\enquote{I Ching,}} 
following the now-obsolete Wade-Giles system: modern Romanization 
of almost all modern Chinese texts follows the Hanyu Pinyin standard used here. 
See [huang].

\end{document}

To use ctex rather than luatexja-fontspec, use its commands to set the CJK fonts, i.e. \newCJKmainfont. It doesn’t play well with csquotes, so you might be forced to \DeclareQuoteStyle.

To stick with polyglossia and use \chinesefont, you would want to add language tagging, e.g. \textchinese{易经}. In XeLaTeX, you could configure ucharclasses to automatically tag Chinese characters as Chinese for you.

Finally, you could use babel. It does not support all the features of ctex or luatexja, but it suffices to insert words and short phrases, written horizontally. Unlike luatexja or ctex, it supports multiple ideographic writing systems in the same document.

You mention in the comments that you have a lot of text already tagged for polyglossia and dread changing it. You can configure babel to support polyglossia user commands, such as \textenglish, and also to auto-detect which script you’re typing in so you don’t need to tag many languages at all.

\documentclass[12pt,a4paper,oneside]{scrbook}
\tracinglostchars=2
\usepackage[english]{babel}
\usepackage{fontspec}
\usepackage{csquotes}
%\setotherlanguage{chinese}
\usepackage{xstring}

\babelprovide[import=zh-hant, onchar=ids fonts]{chinese}
% Or import=zh-hans for Simplified Chinese.

\defaultfontfeatures{ Ligatures=TeX,
                      Scale=MatchUppercase }

\babelfont{rm}
          [Ligatures=Common, Scale=1.0]{Latin Modern Roman}
\babelfont[chinese]{rm}
          [Renderer=HarfBuzz]{AR PL Uming TW}

% Enable \textenglish, \begin{english}, etc.
\babeltags{english=english}
\babeltags{chinese=chinese}

\begin{document}

The common transliteration of 易经 is {\enquote{I Ching,}} 
following the now-obsolete Wade-Giles system: modern Romanization 
of almost all modern Chinese texts follows the Hanyu Pinyin standard used here. 
See [huang].

\end{document}