Predictive Text

Firstly, go to Settings > General > Keyboard on your iPhone. A long list of options should come up, regardless of the number of keyboard languages that you have added. The ones you wish to uncheck is the one entitled 'Predictive'. If you have already unchecked it (which I would assume is what you meant), then you should also ensure that, on that same Keyboard screen, under Settings > General > Keyboard > Text Replacement, there are no phrases or abbreviations that are to be changed when you type them; there should be none in the list. One that is present by default is "omw" --> "On my way!". Please also note that if you often use Slide to Type, then there is no way of turning predictive text off, as that is one of the key ways that this feature works. Let me know if you need further assistance.