Emjoi craze a smiley-faced success story

'World's fastest-growing language' meeting a need, according to creator

From a humble smiley face with a box mouth and inverted V's for eyes, crude weather symbols and a rudimentary heart - emoji have exploded into the world's fastest-growing language.

There are now about 1,800 emoji characters. They cover everything from emotions and food to professions, are racially diverse and have become an integral part of the smartphone age.