Parker Mantell overcomes stutter to deliver inspiring graduation speech to his fellow students...

When Parker Mantell stepped to the podium to deliver Indiana University’s commencement speech, he immediately confessed to his fellow graduates that he may not have been the obvious choice to deliver the address.

“As a person who stutters, I can be no more certain that, in this room and in this hall, are thousands of people who far more talented at public speaking than I am,” he told the crowd. “At the same time, however, I can be no more certain that the message I have to share is one that must be heard.”

Mantell, who graduated May 10 with a political science degree, urged his classmates to rise above any doubts they have about their abilities. He cited Beethoven’s deafness, Ray Charles’ blindness and Albert Einstein’s dyslexia as examples of disabilities that failed to get in the way of their success.

President Franklin Roosevelt, Mantell also noted, “couldn’t walk. Imagine if he had never dared to run. Imagine what you are depriving our world of if you never dare to achieve your purpose."

The 21-year-old says his speech, which has since gone viral, was all about encouraging his fellow students.

"I felt incredibly blessed to be presented with the platform to inspire others," he told TODAY.com via email. "It is my greatest hope that I have done so in the days following my speech. Ultimately, however, none of this is about me or what I have done — it's about people becoming what I know they can be."

Selected for the opportunity after responding to a call for applications, Martell says he knew that speaking in front of over 17,000 people "would be nerve-wracking" but that he didn't want to regret not taking the chance. He prepared for the commencement address by videotaping himself practicing every day and taking notes on his performance.

In his speech, Mantell credits Indiana University for pushing him beyond his expectations, rather than keeping them in check because of his speech impediment. That encouraged him to go after numerous high-profile internships that found him answering calls for House Majority Leader Eric Cantor, conducting tours of the Capitol for Florida Sen. Marco Rubio, and working in the office of New Jersey Gov. Chris Christie.

“I mention those experiences not out of individual pride or out of vanity, but rather out of desire to share Indiana University’s role in dispelling the idea that someone who is barely able to talk for himself can dream big enough to talk for public servants,” he said. “While any other university might have instructed me to manage those expectations, IU taught me to grow them.”

Martell, who says he'd like to pursue a career in public service — whether that be through government, politics or law — urged his classmates to reach for their dreams, regardless of the challenges that lie before them.

“Doubt, as has been observed, kills more dreams than failure ever will,” he said. “Yet if doubt were to be a disease, its cure would be confidence.”