Unlike other applications, Word 2011 does not process all the instructions contained in the GreekKeys Unicode keyboards. Several keyboard shortcuts do not work (such as command-b, command-z, command-w), and the "terminator" definitions are ignored, so that following a deadkey diacritic with a mistyped letter, such as typing b (beta) instead of v (omega) after option-3 (circumflex), produces gibberish that requires an extensive deletion to remove.
During the preparation of GreekKeys 2015, it has finally been determined what is the proper format for identifying the keyboards as Greek, and once this identification is present, Word 2011 works properly.
Until the new version of GreekKeys is released later in 2015, a repair is offered for current users who have GKUall.bundle installed (the standard installation of GreekKeys Unicode 2008). Please visit http://apagreekkeys.org/Word2011fix.html