W/the new IOS 8 update, there are some changes to the functioning of the keyboard of which folks might wish to be aware.
First, it appears that 2 keyboards are now enabled by default--1 localized to your language & another called emoji. Emoji are icons that symbolize different things, & this keyboard was causing a client of mine some severe grief, as it was always speaking icons & generally causing her IPhone to freeze till she went into Settings > General > Keyboard & deleted it. So--if your keyboard's acting wonky after updating, this is potentially something to check.
Next, you might wish to note that predictive, autotext, & spellcheck are also turned on by default. While some folks may find these features useful, they can create additional chatter which can be confusing for some. Thus, if you're hearing words being spoken while you type, & you find it distracting, that might be the reason, & disabling that feature--at the risk of potentially having to do more typing--may help.
Just some initial impressions after the upgrade.