Background and Aim: Hearing loss results in impairment of  muscles coordination and survival essential that are engaged in motor speech timing tasks. It will negatively affect the acquisition of speech sounds. The purpose of this study was to compare the oral diadochokinesis in normal-hearing and hearing - impaired adolescents
Materials and Methods: This research was conducted on sixty-one adolescents aged 15-18 years old. Forty-six had moderately severe, severe, or profound hearing loss and fifteen were normal. The time spent to perform each oral diadochokinesis tasks was measured by speech analyzer of Dr. speech software, version four.
Results: Results indicated that hearing - impaired performed significantly slower on all speech timing tasks than their normal hearing peers except those with moderately severe hearing-impaired group. There were significant differences between profound hearing-impaired group and both other groups.
Conclusion: The results of this study point out  the motor speech problems in hearing impairment. The differences, in general, indicate that speech-timing coordination deficits are compromise with hearing loss degree.