Kinds of Sentences.  What kinds of sentences shall a speaker construct as he speaks?  That there is a difference between those a person composes when he writes and those the same person is likely to evolve when he speaks is realized by everyone.  We hear that a speaker is “booky,” or conversational, that he is stilted or lively, that he is too formal, that his discourse is dull and flat.  To a great degree these criticisms are based upon the sentence structure.

The Simple Sentence.  The simple sentence contains only one subject and one predicate.  The complex sentence contains one independent clause and at least one subordinate clause.  The compound sentence contains two or more independent clauses.  It would be good advice to urge the employment of the simple sentence were it not for the fact that a long succession of sentences constructed exactly alike, making the same impression of form and sound and length, is likely to produce a deadly monotony of emphasis and pause, an impression of immaturity on the part of the speaker and of lack of skill in molding his phrases.  Yet, in the main, the simple sentence is a valuable kind to know how to deliver.  Containing but a single thought it is likely to make a definite impression upon a listener.  It offers him not too much to grasp.  It leads him a single step along the way.  It speaks clearly, concisely.  Its advantages follow from its qualities.  At the beginning of addresses it is especially efficient in leading the audience at the same rate—­slowly, it should be—­as the speaker.  In intricate explanation, in close reasoning, in matters of paramount importance, it should be employed.

Management of the short, simple sentence in written prose is difficult.  In spoken discourse, as well, it is so easy to fall into the First Primer style that while the advantages of the use of the simple sentence are great, the ability to produce good sentences in succession must be developed.

The Complex Sentence.  The complex sentence offers a good form for introducing pertinent, minor details, which are necessary, yet which do not merit inclusion in the general level of the speech.  Aided by proper pitch and inflection of the voice, they can be skilfully subordinated to main ideas, yet introduced so adroitly that they at times relieve attention, at others briefly explain, at others keep adding up in a series the effect of which is a large total.  Frequently such sentences indicate clearly the progress of the discussion.  A topic introduced in a subordinate clause may later be raised to more importance without abruptness, for hearers are already familiar with it.  A topic already treated may be recalled by citation in a later clause.  So various parts of a speech may be closely knit together to present a coherent, progressive, unified whole.

In easily grasped general, descriptive, narrative, explanatory material, complex sentences will allow the covering of a wide field, or a long time, in short order by condensing facts into the few words of subordinate clauses.