Complex sentence: A lipspeaker may be asked to use their voice so that the lipreader can benefit from any residual hearing, and can also help in clarifying the deaf person's communication with hearing listeners.
Split into simpler sentences: A lipspeaker may work silently, or may be asked to use their voice so that the lipreader can benefit from any residual hearing. The lipspeaker can also help in clarifying the deaf person's communication with hearing listeners.