Keyboard extremely sluggish on iOS7 with iPhone 4s

I've upgraded to iOS7 on my iPhone 4s. The keyboard, regardless of what I am doing, either texting or entering email, is extremely sluggish - 5 second interval between keystrokes.

What are some ways to troubleshoot this problem?

Solution 1:

Try Settings > General > Reset all settings. I was having the same problem and that fixed it on my 4s.

Solution 2:

Try turning off "Documents and Data" in iCloud. It should make typing faster. You can turn it back on, but if you go to iCloud Storage and Data, it will start lagging again. You then must turn off "Documents and Data" once more.

This info was in the comments of this review: http://www.gottabemobile.com/2013/09/18/ios-7-iphone-4s-first-impressions-performance/