Well i guess in a way MSword already does that with its spell checker.
if you typed "teh" with T9 you get the options:
tdh,tdg,tdi,teh,teg,tei,tfi,tfg,tfh
ueg,ueh,vei,udh,udg,udi,ufi,ufg,
vfi,vfg,vfh,vei,veg,veh,vdh,vdg,vdi
So wouldnt really help you out
T9 only works when you type correctly, but it means rather than scrolling through each keys several options (e.g. 2 = a,b & c ) it works out the most suitable word.
e.g. type 2,2,2 on T9, and you will get "cab" as thats the only word from the combination of ABC
