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Enjoying one last visit to his native Janesville, Wisc., before introducing himself to an estimated television audience of 20 million Americans, Rep. Paul Ryan has been quietly preparing the speech of his life: his address before the Republican National Convention that will formally anoint the 42-year-old as the party's vice presidential nominee.

"These were not late-night crash sessions," said a Romney-Ryan campaign aide familiar with Ryan's means of preparation.  The aide spoke under condition of anonymity because he was not authorized to speak publicly about the congressman's secretive work on the speech at his home in southern Wisconsin.

According to campaign sources, Ryan practiced the address at junctures specifically chosen so as not to interfere with family time: between church attendance Sunday morning and family dinner on Sunday night. As well, aides said Ryan made use of teleprompters that were set "exactly as they will be in Tampa" on Wednesday night, when Ryan will speak to a coveted primetime audience.

The teleprompters were placed at precisely the same distance from the speaker, and from one another, as the candidate will see when he takes the stage at the Tampa Bay Times Forum, site of the GOP's nominating convention.

Members of Ryan's staff contacted by Fox News could not specify the expected length of the speech -- "we're still playing with that," an aide said -- but acceptance speeches at national conventions typically last between thirty minutes to an hour.

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"Some of the ideas in his convention speech were teased in his Janesville speech" on Monday, one Ryan aide said. Joined by his wife Janna and their three children inside a packed gymnasium at Craig High School, Ryan used his hometown sendoff to celebrate the Midwestern values that helped him prevail through difficult times.

"We look out for one another," Ryan said.  "That's what's so special.  That's what government can't replace or displace."

Ryan's emphasis on caring communities will be central to his efforts to dispel concerns -- eagerly stoked by the Obama-Biden campaign and its Democratic allies -- that the plan put forward by the House Budget chair to rein in spending on federal entitlement programs, like Social Security and Medicare, will strip vulnerable Americans of a vital safety net.

Asked how the two men on the Romney-Ryan ticket will differentiate themselves in their convention speeches, campaign officials sought to lower expectations for the kind of oratorical flash that then-Sen. Barack Obama displayed in 2008.

"They're different guys with different backgrounds," a GOP campaign aide told Fox News on Monday, "and they'll each use their speech to tell their own stories of who they each are.

"But they'll also both present the Romney-Ryan vision for the country in a unified way."

It took the new vice presidential candidate a little while to adapt to the rigors and hyper-scrutiny of the national stage. While Ryan has drawn -- and invariably delighted -- overflow crowds at virtually all of his rallies in critical swing states, close watchers observed the wonky and impassioned veteran of the House floor flub several of the applause lines crafted for his earliest outings on the presidential campaign trail.

To ease this transition, senior Republicans in Washington have thrown top-level talent at Ryan behind the scenes, in an effort to bolster the seven-term lawmaker as a speaker and debater.

Two of House Speaker John Boehner's top communications aides were detailed to the Ryan press operation.  And John McConnell and Matthew Scully, two speechwriting veterans from the Bush-Cheney White House, traveled with the candidate during his first week on the GOP ticket, getting a sense of Ryan's rhetoric and oratorical rhythms in order to help him draft his acceptance speech to the convention.

Aides cautioned, however, that Ryan, composing in longhand, had already written much of the address himself in recent weeks.

In addition to press aides and speechwriters, Ryan's traveling campaign has also benefited from the return of numerous "advance" staffers who had previously served on the Bush-Cheney campaign in 2004 and the McCain-Palin operation four years later.  These are mostly young people who show up at the site of a campaign rally ahead of time, forever speaking into the tiny microphones in their sleeves to ensure the biggest possible crowd and smoothest flow of events.

However, campaign trail veterans also spotted at Ryan's side during the Iowa State Fair, on August 13, a dapper, gray-haired man in eyeglasses: legendary advance man Rick Ahearn, the Reagan White House staffer who can be seen in vintage video footage walking just ahead of President Reagan in the moments before he was shot and wounded by a would-be assassin in March 1981. Ahearn's involvement in presidential politics dates back to the 1968 campaign season.

Beyond the convention speech, another major performance -- and high-risk opportunity for Ryan to use to communicate with Americans -- looms on the horizon: the October 11 debate between Ryan and incumbent Vice President Joe Biden, to be held in Danville, Kentucky.

It was disclosed on Monday that Sen. Rob Portman, the cool and even-tempered Ohio Republican who many envisioned Mitt Romney choosing as his running mate before Ryan's selection was announced, will play the role of President Obama in Romney's mock debate sessions.

Aides to Ryan refused to say on Monday who will assume the role of Biden, a notoriously garrulous and sometimes gaffe-prone speaker, in Ryan's debate preps.

"We're 90 percent of the way there" toward finalizing the selection, an aide told Fox News.