Answer:
A common characteristic of a successful speech's structure is Repetition of key ideas or phrases
Step-by-step explanation:
Repetition is a very recurrent literary device in successful speeches, as this technique makes the message sound more relevant and memorable to the audience, besides this gives an specific rhythm to the speech that also helps to attract the attention of the audience not only during the time that it takes to listen to it but even after it, this can also make it emotive and appealing.