well.

Change of pitch is a stumbling block for almost all beginners, and for
many experienced speakers also. This is especially true when the words
of the speech have been memorized.

If you wish to hear how pitch-monotony sounds, strike the same note on
the piano over and over again. You have in your speaking voice a range
of pitch from high to low, with a great many shades between the
extremes. With all these notes available there is no excuse for
offending the ears and taste of your audience by continually using the
one note. True, the reiteration of the same tone in music--as in pedal
point on an organ composition--may be made the foundation of beauty, for
the harmony weaving about that one basic tone produces a consistent,
insistent quality not felt in pure variety of chord sequences. In like
manner the intoning voice in a ritual may--though it rarely
does--possess a solemn beauty. But the public speaker should shun the
monotone as he would a pestilence.


_Continual Change of Pitch is Nature's Highest Method_

In our search for the principles of efficiency we must continually go
back to nature. Listen--really listen--to the birds sing. Which of these
feathered tribes are most pleasing in their vocal efforts: those whose
voices, though sweet, have little or no range, or those that, like the
canary, the lark, and the nightingale, not only possess a considerable
range but utter their notes in continual variety of combinations? Even a
sweet-toned chirp, when reiterated without change, may grow maddening to
the enforced listener.