Difference between Public Speaking and Acting.  In practically all the aspects of public speaking you deliver your own thoughts in your own words.  In dramatic presentation you deliver the words already written by some one else; and in addition, while you are delivering these remarks you speak as though you were no longer yourself, but a totally different person.  This is the chief distinction between speaking in public and acting.  While you must memorize the lines you deliver when you try to act like a character other than yourself, speeches in dramatic production are not like usual memorized selections.  Usually a memorized selection does not express the feelings or opinions of a certain character, but is likely to be descriptive or narrative.  Both prose and verse passages contain more than the uttered words of a single person.

As preparation for exercise in dramatics, whether simple or elaborate, training in memorizing and practice in speaking are extremely valuable.  Memorizing may make the material grow so familiar that it loses its interest for the speaker.  Pupils frequently recite committed material so listlessly that they merely bore hearers.  Such a disposition to monotony should be neutralized by the ability to speak well in public.

Naturalness and Sincerity.  When you speak lines from a play inject as much naturalness and sincerity into your delivery as you can command.  Speak the words as though they really express your own ideas and feelings.  If you feel that you must exaggerate slightly because of the impression the remark is intended to make, rely more upon emphasis than upon any other device to secure an effect.  Never slip into an affected manner of delivering any speech.  No matter what kind of acting you have seen upon amateur or professional stage, you must remember that moderation is the first essential of the best acting.  Recall what Shakespeare had Hamlet say to the players.

Nor do not saw the air too much with your hand, thus:  but use all gently; for in the very torrent, tempest, and, as I may say, whirlwind of your passion, you must acquire and beget a temperance that may give it smoothness.  Oh, it offends me to the soul to hear a robustious, periwig-pated fellow tear a passion to tatters, to very rags, to split the ears of the groundlings, who for the most part are capable of nothing but inexplicable dumb-shows and noise.

Character Delineation.  In taking part in a play you must do more than simply recite words spoken by some one other than yourself.  You must really act like that person.  This adds to the simple delivery of speeches all those other traits by which persons in real life are different from one another.  Such complete identification of your personality with that of the person you are trying to represent in a play is termed character delineation, or characterization.