A standard telephone keypad, with four rows of three keys each. The top row consists of 1, 2, and 3, with keys continuing down in order until the last row, which is usually *, 0, and ...

Predictive text is most useful on 12-key and 20-key phone keypads, but it can be used on QWERTY text keyboards as well. There are a handful of competing technologies, including T9 from Nuance ...