A teacher in the class should keep the pitch of his voice

A teacher should pitch the voice high enough so that every student, even at the back, hears the message clearly.

A low pitch fails to reach the whole class and strains the listeners.

A moderate pitch may still not carry across a large or noisy room.

Alternating low and high inconsistently distracts and tires the listeners.

Audibility is a basic requirement of effective oral communication in class.

Voice modulation, varying pitch for emphasis, sustains student attention.