To investigate the problem of speechreading failure, a battery of tests was administered to 60 deaf children, half of them poor learners and half good. Results indicated that those who developed speechreading did so at an early age and could deal with words, phrases, and sentences spoken at any rate whereas poor learners comprehended only words spoken slowly. Good learners were superior on measures of intellectual ability, reading comprehension and written language, and sequential and spatial memory. Factorial analyses also indicated that the good learners had more highly integrated and organized mental abilities. Neurological studies revealed more positive neurological signs in poor learners; electroencephalographic studies did not discriminate significantly between the good and poor learners but did distinguish between the brain functioning of deaf and hearing children; ophthalmological studies indicated a high incidence of visual abnormalities in both experimental groups. (Author/JD)