Go to "Open Settings", go to "language & input", go to the right of Samsung Keyboard tap the "gear icon", then you can turn Predictive text OFF.
I just got my Centura and was looking for a way to turn it off as well. When you are texting there is a "gear" icon to the left of the space bar, push that and it will bring you to a settings menu where you can turn the predictive text off.
there is no language and keyboarding there is only language and input. under input there is only keyboarding and input methjods. google voice typing or samsung keyboard...there is NOTHING that offers predictive texting as an option
Open Settings, go to language and keyboard and go to the settings of the keyboard you are using and turn predictive texting off.
Let me know if you were able to turn it off. Good luck! :)