Wilson repeats several words, like “humanity”, “democracy”, peace”, “justice”, and “freedom”, which become motifs of his speech. This way, the audience is constantly reminded of the values and principles that America associates itself with.
In the following example, Wilson relies on the repetition of “we” at the beginning of consequent sentences:
We have no selfish ends to serve. We desire no conquest, no dominion. We seek no indemnities for ourselves, no material compensation for the sacrifices we shall freely make. We are but one of the champions of the rights of mankind. We shall be satisfied when those rights have been made as secure as the faith and the freedom of nations can make them.
Here, the repetition of “we” helps Wilson portray America as honest and willing to protect democracy and the freedom of nations. At the same time, the repetition of “no” shows that America does not have hidden political interests, like Germany.
When Wilson talks about the consequences of America joining the war, he also relies on repetition:
It will involve the utmost practicable cooperation (…) It will involve the organization and mobilization of all the material resources of the country (…) It will involve the immediate full equipment of the Navy (…) It will involve the immediate addition to the armed forces of the United States (…) It will involve also, of course, the granting of adequate credits to the Government
In this example, repetition helps Wilson organize his ideas and touch on each aspect he considers relevant. Moreover, repetition helps the audience follow Wilson’s idea in an organized way.