Why does my IPHONE 4S enter text in a short message, and then press and hold the delete key, and the content will be deleted one by one? How to solve it?

At first, the deletion is a smooth deletion of one word at a time, and then more than 10 bytes are deleted, because deleting multiple bytes at a time is Apple's optimization, which is actually a very humanized design. Every ios system is like this.

If you want to delete it at once, just shake the iphone and the option to cancel typing will pop up.