How we change what others think, feel, believe and do
Osgood et al (1957) identified three dimensions along which we create meaning. Every message may have more or less along each dimension, thus placing the meaning in three-dimensional (although still rather virtual) space.
The semantics of a phrase or sentence depends on such as the ordering of the words, the choice of specific words and the other phrases and sentences that provide the wider lexical context.
The semantic axis holds possible meanings of the words, one of which will be selected, based on the positioning along the other two axes.
Using semantic methods of persuasion includes using metaphor, ambiguous words and sentence structures that 'say things without saying them' and leads the listener into putting themselves into situations. Semantics may also be applied to actions, and body language adds huge meaning to communications.
Words have function within sentences and speeches, supporting one another and creating patterns that may have subtle and deliberate impact. The functional axis adds what the words do, giving them purpose, attaching them to the outer world of things or the inner world of ideas. The words may identify issues, assign cause, propose solution, excite audiences.
People make mistakes with words, for example in the signal response of confusing the map with the territory. These errors can be deliberately caused by canny speakers whose intent is that the words function as persuasive elements.
Thematic (or textural) wording adds unity and overall feel to the message. They may all combine to add vision, tell a story, build a sense of purpose.
Themes may be contrastive, such as light and dark or good and bad. They may be subject-based such as children or dogs. They may make heavy use of metaphor to suggest and develop a bigger picture. Themes may also use the sounds of words, creating poetic hammering of consonants or flows of rhythm and rhyme.
So when composing message, think not only of the basic meaning, but what you want to words to do. Also use themes to build unity into the whole message.
Osgood, C.E., Suci, G.J., Tannenbaum, P.H. (1957). The Measurement of Meaning, University of Illinois Press