Washington - Throughout his presidency, Barack Obama - an eloquent and talented orator with undeniable charisma - has taken particular care in the writing of his speeches, several of which have marked milestones in his White House tenure. "Some of the craft of writing a good speech is identical to any other good writing," he told The New York Times in an interview published on Monday."Is that word necessary? Is it the right word? Is there a rhythm to it that feels good? How does it sound aloud?"For Obama's chief speechwriter Cody Keenan, each address is "a way to tell a story," and the balancing act each time is to offer a vision on an issue without getting trapped by the "very real danger of being out of touch.""There were arguments internally in the early years of the administration about how optimistic and forward looking you could get in economic speeches when unemployment is still at like 8 or 9 percent," Keenan told AFP.Obama, a former lecturer in constitutional law at the University of Chicago, is very involved in drafting his speeches."We will usually sit down with him in the Oval Office and he will just talk and we will type it out and that gives us something to go work with," Keenan said."We'll spend a couple of days, write a draft, give it to him. If he doesn't like it, he will take out a yellow legal pad and write his thoughts and if he does, he will start outlining the whole thing," he said.It usually takes three or four drafts to arrive at a final product... which are often tweaked at the last minute anyway.Here's a look at five key speeches in the career of the 44th president of the United States.- Boston: Disrupting the political scene -July 27, 2004"There's not a liberal America and a conservative America; there's the United States of America. There's not a black America and white America and Latino America and Asian America; there's the United States of America."Then unknown on the national scene, a young senator from Illinois named Barack Hussein Obama - the son of a Kenyan father and a white American mother - was the breakout star of the 2004 Democratic convention."Probably his most successful speech was the one where he introduced himself to the country for the first time," Keenan said."All he did there was tell the country's story and tell his own story and weave them together."- Cairo: Appealing to the Muslim world -June 4, 2009"I've come here to Cairo to seek a new beginning between the United States and Muslims around the world, one based on mutual interest and mutual respect."Addressing the world's 1.5 billion Muslims with the traditional Arabic greeting "Salam alaikum," Obama called for ending "this cycle of suspicion and discord."- Oslo: War and peace -December 10, 2009"To say that force may sometimes be necessary is not a call to cynicism - it is a recognition of history; the imperfections of man and the limits of reason."Less than a year after taking office, Obama delivered his views on the conditions for using force as he accepted the Nobel Peace Prize.He also gave a nod to the "considerable controversy" generated by his winning the award."I am at the beginning, and not the end, of my labours on the world stage," he pointed out.- Selma: The march continues -March 7, 2015"We just need to open our eyes, and our ears, and our hearts to know that this nation's racial history still casts its long shadow upon us." Speaking at the Edmund Pettus Bridge 50 years after the brutal repression of a peaceful protest there, America's first black president rallied a new generation to the spirit of the civil rights struggle.Accompanied by his wife Michelle, daughters Malia and Sasha, and 50 others, Obama then walked across the infamous bridge over the Alabama River.- Charleston: Amazing Grace -June 26, 2015"For too long, we've been blind to the way past injustices continue to shape the present."Obama made the pronouncement during a rousing eulogy for pastor Clementa Pinckney and eight members of his congregation at the historic "Mother Emanuel" black church, who were killed in a hail of gunfire unleashed by a white supremacist.After focusing on America's struggles with race and guns in a sermon-like address, he paused - and then began singing "Amazing Grace." The thousands of mourners joined in."We had the lyrics in there twice, in the middle and then at the end," Keenan said."That morning, we were flying on the helicopter to (Joint Base Andrews) and he said, 'You know, I might sing the second one if it feels right.'""I watched from the plane, on the tarmac, and you could tell within about three minutes, with that crowd there and the organ playing while he was speaking, that, of course, he was going to sing it."