The words role and roll are homophones: they sound alike but have different meanings.
The noun role refers to a character played by a performer or a part that a person has in some activity or situation.
Roll has many senses. As a noun, it may refer to a portion of bread or a list of names of persons belonging to a group. As a verb, roll means to move, wrap, or throw.
Examples "The role of a writer is not to say what we all can say, but what we are unable to say."(Anais Nin)
"The two of us and her mouthy teen-age son opened some presents, and then we went to this steak house near her apartment. I wasn't hungry. I had some soup and a hot roll."
(Raymond Carver, "Where I'm Calling From." The New Yorker, 1983)
"When they call the roll in the Senate, the Senators do not know whether to answer 'Present' or 'Not Guilty.'"(Theodore Roosevelt)
Each player may roll the dice only once per turn.
"The way that he lifted and handled his violin! First, he would roll up the sleeves of his white shirt and remove his necktie and loosen his collar . . .."
(Tennessee Williams, "The Resemblance Between a Violin Case and a Coffin." Flair, 1951)
The expression on a roll means a streak of success or a period of good luck.
"Indonesia has been on a roll since it emerged virtually untouched from the 2008 financial crisis. In 2009, it joined the Group of 20 large economies. It won its first investment-grade credit ratings in more than a decade in late 2011 and early 2012, and its gross domestic product has expanded at a steady rate of more than 6 percent for the last three years."
(Joe Cochrane, "Multinationals Hasten to Invest in Indonesia." The New York Times, April 23, 2013)
The expression roll around means to return, recur, or arrive again.
"Whenever a gift-getting holiday would roll around in which unearned gains were supposedly delivered by a mystical third party, I always forced her to tell me more and more about these Santa Claus and Easter Bunny and Tooth Fairy people."
(Paul Feig, Kick Me: Adventures in Adolescence. Three Rivers Press, 2002)