Washington — Tradition suggests it's time for Donald Trump to set aside the say-anything speaking style and rise to the inaugural moment.But bucking tradition, or ignoring it altogether, is what got Donald Trump to his inaugural moment.When Trump stands on the west front of the Capitol on Friday and delivers his inaugural address, all sides will be waiting to see whether he comes bearing a unifying message for a divided nation or decides to play up his persona as a disrupter of the established order.How Trump tends to that balancing act, in both style and content, will be a telling launch for his presidency."The inaugural is an address that is meant for the ages," said Kathleen Hall Jamieson, a communications professor and director of the Annenberg Public Policy Center at the University of Pennsylvania. "In particular, it's important when you've had a divisive election. You need to become president of all of the people, including those who vehemently opposed your election."Trump seems to get that.He's spoken admiringly in recent weeks about the speeches of past presidents Ronald Reagan and John F. Kennedy, and is said to be deeply involved in preparing his address. He's expected to deliver a personal speech, while returning to some of the big themes of his campaign, including a deep love of country.Trump told Fox on Tuesday that he'll start his address with words of thanks to "everybody," including President Barack Obama and his wife, Michelle, for being "so gracious".The president-elect showed he can deliver a straight-forward, prepared address at the Republican convention, where he largely stuck to a script and shut down anti-Hillary Clinton chants of "lock her up" from the crowd of GOP loyalists.But that address was strikingly dark in tone, sketching a portrait of an America in crisis, and he later embraced that chant from supporters at his freewheeling campaign rallies.Words of adviceThe inaugural address, by contrast, needs to be "an inherently aspirational speech," said Michael Gerson, who wrote speeches for President George W. Bush and is a frequent Trump critic. "It has to be about the future and about your vision."Veteran speechwriters have plenty of other advice for Trump and his chief wordsmith, Stephen Miller. Keep it short. Don't overdo the gravitas. Don't gloat, the victory tour is over. No deviations from the script.Oh, and don't undo a successful inaugural address with an intemperate tweet — or two or three — a few hours later.While Trump used his victory speech on Election Night to sound a call to "come together as one united people", his tweets since then have featured name calling, score settling and petulance.Wayne Fields, a Washington University expert on presidential rhetoric, said Trump is in an awkward situation, going into his inaugural address as a man who seems to regard precise language with contempt "rather than respect."After all, this is a candidate who revelled in taking juvenile potshots during the campaign, labelling his rivals "stupid", “dumb" and "bad"."I know words," he declared at one rally. "I have the best words. But there's no better word than stupid, right?"Even if Trump delivers a statesmanlike speech that hits all the right notes, Fields says, "nobody would know how to receive it or who it was coming from or how seriously to take it. It's a huge challenge."Any reframing of Trump's tone for the presidency — if he wanted to do that — would require a consistent, longer-term shift, Fields said.Trump does go into the speech with the benefit of low expectations: His off-the-cuff and often inflammatory style has long been a big part of his appeal. The soaring rhetoric of Obama, for example, simply wouldn't ring true."Because of the high level of attention and the low expectations, he's far more likely to exceed expectations," Jamieson said.At the same time, Gerson cautions, Trump faces an extra hurdle in his inaugural address because he won the election by dividing the country."The method that he won creates the initial challenge of his presidency, which is to rally people broadly around his agenda and vision," he said.Trump also knows his audience will include plenty of supporters who elected him to challenge the status quo. An address that doesn't offer any flavour of Trump-the-disruptor could disappoint those eager for a sea change in the ways of Washington.Beyond Friday, there is the larger question of how Trump will adjust his speaking style over the next four years. His past pledges to "act more presidential" when the time is right are coming due."Any president is going to have to learn how to make use of good speeches," said Gerson, noting that presidents may have to speak at three public events in a given day. "That may be different from anything he's ever experienced before, because the campaign rewarded spontaneity and being extemporaneous. There are huge portions of the presidency where that can't be the case."