it depends on the type of the research you'll be using. if its qualitative or quantitative.
one is *stay or go* another is * Acquainted With The Night*
In a speech, there are certain factors we have to consider:
1.) The tone of your voice
2.) The flow of your speech
3.) Your manneurisms while presenting
All of these things matter in presenting a speech.
The advantages of giving a memorized speech is that you would have been prepared for it beforehand; you know the structure, the message, and what you're supposed to say in front of the stage. If you're not very good at producing words in a short manner of time, memorizing can be a good method to do it.
By memorizing speeches (especially ones made by yourself), you will be given a chance to edit your speech to make the flow more smooth, the grammar made better, the message more clearer, and overall, make the speech better than its original state.
By memorizing speeches made by somone else, you will earn the opportnity to view other renditions of this speech done by other people, or the author itself. This will give you a chance to review the message and be able to convey it as intended by the author in a better way.
While delivering a memorized speech, these factors can be our greatest friend, or our worst enemy. Since a memorized speech comes from a written speech, interpretation is free for anyone who reads it, and conveys it as well. When you recite a speech made by someone else, there is a very high chance that you will not be able to convey the message the same way it was intended to be conveyed. Things such as the tone of your voice, the way you organize the flow, and how you act, will be different.
Reciting memorized speeches, especially for beginners, sometimes make them look robotic. It makes them sound like they're just dictating, and not giving a speech.