I've actually made a teckit mapping for TIPA before. But this was just for the A-Z, 0-9 mappings. It didn't include any of the commands involving a backslash. What you could do is to change the definitions of \|, etc. to different, safe/non-TIPA characters/strings (e.g. $| for \|, and $; for \;), and then the teckit mapping would be able to catch them.
A problem you might run into is the handling of the small caps characters. Fonts like Charis SIL have the glyphs at the proper Unicode addresses (and they're actually different from the small caps you get if you use the OpenType small caps feature), but for other fonts, you may need to fake them. I think there's a way to check the presence of a glyph in a font, and from there choose the appropriate behaviour, but this will also require support from outside the teckit mapping. -Andy -------------------------------------------------- Subscriptions, Archive, and List information, etc.: http://tug.org/mailman/listinfo/xetex
