This week Daniel has a quick tip detailing how to add and remove words from your iPhone’s autocorrect dictionary. This is great if you like to use slang or a made-up word, or if your phone autocorrects a word incorrectly.
To delete a word that you've added to auto-correct dictionary in the iPhone 5, you don't have to reset the entire dictionary. Go to SETTING, GENERAL, KEYBOARD In the top right corner, tap EDIT you will be given an option to delete 1 or more words that you've added to the dictionary. Follow the instructions on the screen. That's it.
Sometimes, you might have to shut-down and re-start your iPhone 5 before the changes will take place.
Good luck to all.