Predict text?

in Microsoft word Excel and emails predictive text is fine but keeps changing words by one letter without me selecting that word.
It's a pain having to check each time to ensure words are how I typed them. Take one, PART it changed to HART, FART was chaged to DART RAIN TO PAIN and so on. I think it might be trying to take me over and condition me to act like a Samsong Galaxy A6 tablet.
Thanks in advance