1. Citing gives credit for the ideas (or intellectual content) to the author(s) who wrote or created the material you used.
2. Citing a "credible" or "reliable" source helps lend weight to your argument or point and can bolster your authority as being knowledgeable about the topic of your speech.
3. The citation acts as a permanent address or telephone number. It gives you the information needed to get back to, or obtain a copy of, the material used in your project.
After all, would you want to lug around a computer and hope you can find the website you used or carry all the books and journals with all your notes and bookmarks all the time?
Many departments (but not all) in the College of Liberal Arts will require you to use APA (American Psychological Association) style. For instance, most communication classes will want you to use the APA citation style, but English courses may require you to use MLA (Modern Language Association) style. There are other styles each with unique quirks when it comes to citing websites, audio or visual materials, journals or magazines, books or parts of books; however, regardless of the style, most citations contain the same information. Here's a short video that break down the parts of the most common materials:
For more information on how to read a citation, check out the Basic APA Citations page.
The library has the style manuals behind the reference desk and your instructor may provide you with more information. Consider making an appointment with the Miller Writing Center in the library or one of their satellite venues to help you with your references. Check out some of the links in the box on the right like the Purdue Online Writing Lab (OWL) or the APA Style Blog. You can also look at the other tabs on this page, APA Reference List Example and APA Tutorial for more information.