how Indian Engineers helped stephen Hawking 'talk'

Arun Mehta and vickram crishna

At the request of stephen Hawking, Arun Mehta ,an Indian software developer and a disability activist ,along with Vikram crishna , developed a free and open source software named eLocutor , to allow severely disabled person to write and speak. 

In January 2001 , Stephen Hawking arrived India and attended an international physics seminar at the Tata Institute of Fundamental Research (TIFR) 

Hawking, who had been diagnosed with Lou Gehrig's disease when he was just 21,travelled around Mumbai in a specially redesigned vehicle that could accommodate his wheelchair. 
It was during this time that his aides began reaching out to several people and organizations who could help write a software program that could help Hawkings communicate through his computerised wheelchair.
the men who decided to take up this challenge were Arun Mehta and Vickram crishna .

eLocutor 

Single Button typing and speaking software 
Stephen Hawkings and many like him can only operate a single button ,software that allows them to efficiently enter text into the computer and have it spoken for them 
eLocutor was designed for Hawkings to allow him to Type , Speak and command the computer.