How to access Android language dictionaries
I was having the same issue but in Spanish and i just disabled sms division on the messages option menu and problem solved, no need to hack around dictionaries

EDIT:

Go to "Messages" > Press "Menu" key > Press "Adjustments" (in spanish it says "Ajustes") > Uncheck "SMS Split"

BTW, this question is more suited for the android.stackoverflow.com site.