[XeTeX] On cross-language font selection

[Will Robertson]

Just my two cents before Jonathan chimes in if he's got time...

On 2/15/07, Nikola Lecic <nlecic at eunet.yu> wrote:
> It would be very nice, but that seems to be almost impossible in
> European-only mixing. One who has to mix Latin, Cyrillic (with *all*
> diacritics and language-dependent features) and full polytonic Greek --
> will eventually realise that just a couple of fonts (including the most
> expensive ones!) can do all three things at the same time, *completely*
> and flawlessly.

I think the reason that Jonathan has shied away from such features in
the past is that it's pretty much impossible to contextually "know"
when the text is changing from one language to another. Not only the
fonts have to change, but also the hyphenation patterns and possibly
other bits and pieces of markup/syntax (consider quotation and
punctuation styles).

While it is possible to create specific solutions to these problems
(e.g., when only English and Chinese is mixed it's quite easy to see
where the language changes), there's no way that a generic solution is
possible. At the edges of possibility, imagine a text that mixes
British English and American English (they are hyphenated
differently). Things are only slightly less complicated mixing any
other two roman-alphabet languages.

So in short, even if a single font is used for the entire document (or
a "virtual font" covering the languages you need), more markup is
still required to signal the language switch. Therefore, you can just
as easily change the font at the same time.

Hope this helps,
Will