iPhones and iPod touches may repeatedly trigger the wrong keys when the emoticon add-on Emoji is installed. Users experiencing this issue may find that even the previews of individual keys (which can be viewed by holding a character on the iOS keyboard) are wrong.
This problem can generally be resolved by disabling or uninstalling Emoji. Navigate to Settings > General > Keyboard > International Keyboards > Japanese > Turn Emoji off, or delete the Emoji app altogether.
Some users have reported that simply adding a second keyboard significantly improves this issue. To do so, navigate to Settings > General > Keyboard, then tap “International Keyboards” and add one.
U.S. users have experienced success with adding the English (UK) keyboard.