T9 predictive texting, which let you type words on a 9-button phone keypad by pressing each key only once, grew out of technology first built to help people with disabilities communicate.

Inventors Martin King and Cliff Kushler developed the underlying dictionary-based prediction system, first demoing it as an assistive-communication tool before founding a company to bring it to ordinary phones. T9 became the standard texting method on non-smartphones through the late 1990s and 2000s, teaching a whole generation to type fast with their thumbs long before full keyboards showed up.