Depending on the subject matter, they all may require extensive research.  Though articles are meant purely to inform, both the essay and the speech may employ rhetoric in an effort to persuade. 

The vital difference comes with the pacing.  The spoken word is integrated into the brain differently than the written word.  Phrasing, syntax, sentence length and structure—all of these must be carefully orchestrated for the purposes of an oral presentation. When delivered with skill, a well-written speech leaves a lasting impression. 

Below is a sample speech promoting the importance of universities.  This is an example of a speech that can double as an essay. 

The question “Of what advantage is a college to the community?” first appeared at Indiana University as the opening to the inaugural speech given by its first president, Andrew Wylie, in 1829—almost two hundred years ago.  The question remains with us because it demands a response over and over again.  Some obvious answers present themselves, such as gainful employment.  A university the size of IU has a huge economic impact on a town the size of Bloomington.  All kinds of people in this community depend on the university for income, healthcare insurance, and many other financial benefits.  If we extend our focus beyond the town to the state and the nation, we see that the university contributes to the community by training people for a multitude of important careers.  Our teachers, our doctors, our computer technicians—the list goes on and on of the vast spectrum of occupations that begin with a college degree.  Furthermore, in addition to providing the foundation for entry into many fields, universities conduct the research which assures that our knowledge in these fields continues to expand. 

We could stop here.  These simple responses firmly establish the advantage of a college to the community.  We could stay within these obvious answers and elaborate on them, providing impressive statistics of community employment, inspiring stories of successful careers, and dramatic results of breakthroughs in research.  All of this has weight and validity.  Few people would argue with these claims.  But we shouldn’t stop here—we should look further for less obvious, but perhaps more important answers.  When we make this effort, we see that above and around the tangible and the concrete, the university functions in the community as an invaluable means of transmitting culture, and more specifically, of transmitting vision. 

Some people, in this time of culture wars, would immediately comment that the community actually finds no advantage in some specific elements of culture that universities often transmit.  Without dismissing their argument, we should ask them to step back and consider a broader perspective.  We may encounter, for example, vehement disagreement about which works of literature prove worthy of study—but look at the conversation itself.  Universities generate hotbeds of dialogue, of engagement, of the messy and agonizing effort to put opposing ideas into the crucible of debate and then to see if, through some form of philosophical alchemy, a new truth or a broader understanding can emerge.  Universities do transmit ideas about which books merit acceptance into the canon, but they also transmit a much grander idea—the idea of a dialogue, governed by reason, that seeks to uncover greater knowledge. 

This effort to uncover greater knowledge rests upon the notion that we do not know some things. Such a statement may sound like a simple truism, but the acknowledgement of ignorance has profound implications and an exalted history.  Socrates, whose dictum, “Know thyself,” stands as a cornerstone of the human quest for knowledge, professed his own ignorance in an effort to teach others that the awareness of ignorance marked the beginning of wisdom, the beginning of the pursuit of knowledge.  Students flock to universities implicitly acknowledging that they need to learn, and they perennially show an eagerness to expand their understanding.  Eminent scholars continually explore uncharted terrain because they seek to know that which they still do not know; otherwise, their research efforts would lose all meaning.  Universities act as massive testaments to the fact of ignorance and the possibility of knowledge, and they insist that we can and should increase our understanding of ourselves and our world.  Ignorance of ourselves and our world traps us and holds us back; knowledge liberates us and moves us forward—that guiding vision animates the mission of every university.  It emanates outward and permeates the entire community. 

Not simply an abstract concept, this vision operates as a dynamic force that has a powerful impact on our lives.  Whether we spend years there or never set foot on one college campus, the presence of universities encourages us to continue learning throughout our lives by any means we can.  Universities stand in our communities as monuments heralding a sublime vision.  They also provide employment, career training, and the amazing fruits of research, but their greatest “advantage to our community” may occur when they push us, encourage us, and inspire us to free ourselves from ignorance, and they do this by transmitting a vision of the liberating power of knowledge.