Sorry to tell that I do not like the stock predictive keyboard from Samsung Galaxy S3 as it is annoying and make more mistake to my words and I need more time to correct it. I prefer to original android 4.0 stock keyboard which actually work better for me. If you do not like it too and wish to remove this feature, you can follow steps before to disable/enable it on your Samsung Galaxy S3.
Step by step to disable Samsung Stock Predictive Keyboard
1. Activate your keyboard in any text area.
2. Press the setting icon on the keyboard. You will be seeing few options, but you select the settings icon [the most right icon]
3. Disable the predictive text feature by sliding the button to Off status.
4. You are now free from “correction” from Samsung Galaxy S3 keyboard ^^