Apple Watch Predictive Keyboard

The Apple Watch stays an incomplete product for as long as it doesn't have a keyboard. However, what is the way to give a user a possibility to type the text on such small screen?

We have allocated a fully-functional QWERTY keyboard on the screen. A tap on a screen overlays an area with several symbols at the same time while a device itself chooses the most probable variant – the same way as T9 works.