What is text prediction when text messaging?

Predictive text is an input technology used where one key or button represents many letters, such as on mobile phones and in accessibility technologies. Each key press results in a prediction rather than repeatedly sequencing through the same group of "letters" it represents, in the same, invariable order. Predictive text could allow for an entire Wordto be input by single keypress. Predictive text makes efficient use of fewer device keys to input writing into a text message, ane-mail, an address book, a calendar, and the like.