Parents are eager to have their children learn foreign languages, so why not try sign language? A smartphone application has been developed to teach people up to 99 words. The Hong Kong Sign Language Association spent two months developing the city's first sign language app after receiving a HK$60,000 grant from the Labour and Welfare Bureau. 'The most difficult part of the app development process was the communication between the app developer and me - all based on the exchange of e-mails,' said language instructor Kong Wan-ki, using sign language which was translated by an interpreter. 'A simple problem took more than 10 e-mails to solve because everything had to be written down clearly in words. That's why it took one more month to get the app done,' Kong said. 'Sign language is useful for everyone. It shows respect if people can use basic sign language to communicate with those who have a hearing impairment.' The app contains 99 common signs - including the English alphabet, numbers and simple words - that people can use to communicate with hearing-impaired people. It is free for people to download on their smartphones. Free sets of sign language cards are also available at government departments and business groups. To promote the use of sign language in the city, the Equal Opportunities Commission has organised a series of events in the past few years. In Hong Kong there are about 92,000 hearing-impaired people and about 8,600 deaf people.