This app represents one of the joys of having an Android device — the ability to mess with features as core to the system as the keyboard. It lets you incorporate emoticons and customize how the keyboard looks, and it supports additional plug-ins for more than two dozen languages. The plug-ins require separate, but free, downloads. As far as typing goes, this keyboard is pretty smooth. As compared to the standard Android keyboard, the prediction algorithm could use a little work — but users can set the app to learn new words if they find they want the keyboard to pick up on their personal style over time. Free, with the option of an ad-free upgrade, for Android devices running 2.0 and up.

Hayley Tsukayama