Lack of speech, i.e. dumbness, has long been equated with backwardness, and probably for this reason and because of success in teaching some hearing impaired children to speak, the terms ‘deaf and dumb’ and ‘deaf mute’ have fallen into disrepute. When deafness is profound and prelingual (i.e. congenital or acquired in early infancy), there is a formidable barrier to the development of language. Many deaf children still leave school with poor language, incomprehensible speech and little ability in lip reading and consequently come to rely upon manual communication methods (finger spelling and signing).