Before smartphones took away keyboards and replaced them with slick touchscreens, T9 was the king of software on mobile devices.

The predictive text entry method changed how people composed messages and allowed us to type faster than ever on tiny keyboards. It gave us a glimpse into a world where phones would not just help people talk to each other from anywhere but also allow e-mail and act as instant-messaging devices.

Martin King, one of the inventors behind the T9 input method passed away in Seattle last week, after a five-year battle with cancer. He was 60.

The T9 idea came at a time when text messaging was just taking off. But typing these messages on a tiny keyboards crammed with just a few keys proved to be painful.

T9, or Text on 9 Keys, changed that. It allowed users to enter words by pressing a single key for each letter. Earlier systems had multiple letters associated with each key and users had to select one of them, requiring two or more taps on the phone keyboard.

T9 also combined groups of letters on each phone key with a dictionary ordered by the frequency of the use of the word. This let users type faster by throwing up words they used most frequently first and then letting them access other choices with the press of a key.

Users could also manually add words to be integrated into the T9 software. (Read this amazingly detailed article on how T9 was bornand how it took off.)

T9 transformed how users interacted with their mobile phones. It took people beyond just voice calls on mobile phones, giving them the ability to type out short messages and longer e-mails. In fact, T9 became so popular and widespread it's still around today.

T9 was born out of the work that King and his co-founder Cliff Kushler did in developing products for people with disabilities. King had developed an eye-tracking communications device that would lay the foundation for his company called Tegic Communications in 1995.

As part of their work for the eye-tracking device, King and Kushler looked at the most efficient way to input text using only a few eye positions. That research became the groundwork for a new kind of text input method called T9.

Tegic was sold to AOL in 1999 for $350 million, and Nuance Communications purchased the company in 2007.

In its beautiful tribute to King, the Techflash blog talks about how King tried to solve problems:

King had an uncanny ability to look at problems from various angles, discovering new ways to solve complex issues, recalled Mason Boswell, a Seattle patent attorney who worked closely with the inventor. "He would often ask questions that connected two fields in a way I had not thought of but that clearly pointed the way to interesting innovation," said Boswell. "He also had a point of view five to 10 years into the future, thinking about devices in a way that transcended current hardware limitations and going more to what could be common down the road."

King was diagnosed with cancer five years ago. But it didn't stop him from starting a new company called Exbiblio. Kushler, his co-founder at Tegic, is now part of a company called Swype that is changing text entry on touchscreen phones.

About 4 billion phones worldwide still use T9 software.

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Photo: (Andrew Currie/Flickr)