Answer:
Volume
Step-by-step explanation:
The volume of speech varies from one speaker to another and answers why some talk softly while some speak loudly. It is the volume of speech that determines the loudness of sound. In an oral presentation the first prerequisite for a speaker is to consider if the sound can be heard by each one of the audiences. Microphones may cause volume problems either by producing distracting echo effect or by making speech volume too low. As per the question, Derek needs to work on his volume of speech.