I had heard that iOS 5 would allow you to override the autocorrect dictionary. That feature alone would make the upgrade worthwhile to me. After downloading the latest OS, I went looking for the edit function.
I found a number of references to adding international keyboards, but those weren’t doing the trick for my outdated 3GS.
I did, however, discover the trick. Here’s the easy way to override your dictionary on even the oldest phones.
First, choose Settings -> General -> Keyboard:
Below “International Keyboards,” you will see “Shortcutss”:
Hit “Add New Shortcut”:
Now enter the word you find iPhone continually correcting as both the phrase and the shortcut:
(iPhone changes “hell” to “he’ll”, which I find highly annoying.)
Hit save, and iOS will never correct that word again.
That’s it. No international keyboards. No hoops.