It is a common misconception that raising your voice will make a Deaf person able to hear you. Shouting does not make communication any clearer. Also assuming that a Deaf person can read your lips is wrong; reading lips is extremely difficult. Certain sounds look the same on your mouth, for example “B” and “P”. Deafness is a range. Some people may be able to hear environmental sounds (fire truck, ambulance, thunder), others may be able to hear speech, while others may have no hearing at all.