Be sure that light is not shining in their eyes. If you are not making yourself understood, find a different way of saying the same thing. Be aware that they may have difficulty understanding speech even with a hearing aid. Absence of speech indicates a lack of intelligence. Absence of speech means that a deaf person is physically unable to speak.
All deaf people can lip-read.
Deaf adults always bear deaf children. Hearing aids or cochlear implants enable a deaf person to hear normally. Sign Language is simply mime and gesture and can be learnt easily and rapidly. Sign Language is the same throughout the world. Absence of speech indicates a lack of intelligence.