"Oren" was an excellent (but not so well known) wysiwyg word processor,
working well with hebrew and english (there were some arabic and russian
fonts as well), and doing great with mathematical formulas. The software was
written in a small company named "Shefi Electronics", which to my
knowledge no longer exists.
The latest version I know of was 3.35, intended for MS-dos operation system.
You can find more details here.
Oren can, to some extent, export a file to Tex format; the output requires a lot of work to be actually ready for tex compilation. I wrote a C program that takes this output file and improves it considerably (although usually more work is required). If there is public demand (namely if one of the four users of Oren wish to transfer their files to Tex), I may make the program available here.