Keyboard shortcuts not working...

Try turning predictive text off, and then see if the shortcuts work.

Edit: Sorry, it seems to be working even with predictive ON.

 

This happens every time there is a major IOS Update. This happened again after updating to IOS 8. I also lose the search ability in the Message App. What I do is after updating...I restore my iPhone from my last back up which should bring everything back to normal.

Try it and it will all revert back to your last settings before the update. Hope this helps

 

I remember this happening before after one of the new iOS versions came out, I can't remember which one though. It's quite annoying. For me the only solution is to restart my phone when they stop working. Then if I'm lucky they work again for an hour or so.