> I'm trying to see how much trouble it would be to typeset > a bilingual text parallel by pages, as in, one language on > the recto page, the other on the verso page, synchronized > somehow by paragraph, preferably more or less automagically.
I would say you could do this with a number of custom macros, in the same vein as Ted Harding's suggested solution (your first reference). Format the text into two diversions (one for each language), paragraph by paragraph, and at the end of each pair of paragraphs add space to the diversion with the smaller height, in order to re-synchronize the two diversions. After you have gathered enough text for a full page (you can do this with a trap, but I would probably just check the height after adding each paragraph), write the page header for the first language, output the first diversion onto the page, trapping the overflow into a temporary diversion (like you would do for footnotes), and write the page footer for the first language. Begin a new page, write the page header for the second language, output the second diversion, again trapping the overflow into a second temporary diversion, and write the page footer for the second language. Then, fill the two primary diversions with the still-remaining overflow and continue. That way your manuscript should remain fairly uncluttered (since all the complexity is in the macros), .2B .L1 stuff in language 1 .L2 stuff in language 2 .L1 more stuff in language 1 .L2 more stuff in language 2 .2E with a couple of macros for starting and finishing the dual-language part.