I am trying to find out more about how XeTeX implements line breaking for different languages using
\XeTeXlinebreaklocale. From the XeTeX reference guide:
\XeTeXlinebreaklocale⟨Locale ID⟩: Defines how to break lines for multilingual text.
That's all the information I could find about it, leaving me with several questions:
- What are acceptable values for ⟨Locale ID⟩? In this question the OP arrives at the conclusion that ISO 639-1 language codes are used, but where can I find out which one of these are actually implemented and lead to changes in XeTeX's behavior?
- Where in my TeX Live system would I find a file containing the line breaking information specific to each locale? It seems like it must be baked in into XeTeX the engine directly as it works even if I only load what
xetex.iniloads, which as far as I can see does not include or
\inputany file containing such information.
- Is there any way to find documentation on how exactly the line breaking algorithm changes when a
\XeTeXlinebreaklocalecommand is issued?
Now let me add that I do know that certain XeLaTeX packages handle multilingual line breaking for me, but this is not what I am looking for; I am interested in getting to know what XeTeX does exactly.