Linux is notable as a system that offers extensive sorts of emulation abilities. One can run a variety of word processing software from other platforms on Linux using emulation schemes such as the following:
This freely-available Windows emulator is increasingly able to run Win16 and Win32 applications; some have reported success at running various versions of Microsoft Word.
This GPLed system can run various Win16 (Windows 3.1) applications; I do not know of results with word processors.
DOSEMU is a MS-DOS "infrastructure emulator." People have commonly used it to run WordPerfect 5.1.
None of these are as satisfactory solutions as having something natively running on Linux, but may prove satisfactory for some peoples' purposes.