Adding Extension for Experimental Thai Spelling

As I understand it, the lack of a usable Thai spell-checker for
LibreOffice (unlike, say, a Khmer spell-checker) is due to the Thai
break iterator.  (I had expected Thai and Khmer to face similar
problems, for neither has a visible word separator and syllable
boundaries are often unclear in both.)  Tagging Thai script text as
Khmer does not work (at least, not in Version 3.4.5); the word
boundaries are still determined by the Thai break iterator.

Is it possible to create an experimental alternative to the Thai
break iterator that can be shared with other people as a LibreOffice
extension? I would be prepared to routinely use U+200B ZERO WIDTH SPACE
(ZWSP) to separate words in the Thai script, but I suspect Thais would
not.  Also, I can seem my first useful version fouling up the
rendering of pre-existing text.  I can't work out how to create a break
iterator as an *extension*. Could someone please advise me how, e.g. by
pointing to the documentation or an example.  I can find documentation
for *publishing* an extension, but that does not address *creating* an
extension.

Richard.