As a candidate, Donald J. Trump’s language about the southern border was remarkably simple: He would build a great wall, and Mexico would pay for it. He repeated this promise hundreds of times.

But his language has shifted since his election as president, particularly since the government shutdown last month.

Who will pay for the wall?

Mexico

Mexico, indirectly or through reimbursement

Before becoming the Republican nominee, Mr. Trump rarely got into specifics when saying Mexico would pay for a wall; he simply assured his supporters that it would. No issue was more associated with his candidacy than immigration, and the border wall was the centerpiece of that issue.

After the election, Mr. Trump continued to insist that Mexico would pay for the wall, but began to qualify that it would do so “in the end,” “ultimately,” “indirectly” or through “reimbursement.”

He later said he brought up the wall so frequently because it was what kept his supporters most engaged. “You know,” he told The Times’s editorial writers, “if it gets a little boring, if I see people starting to sort of, maybe thinking about leaving, I can sort of tell the audience, I just say, ‘We will build the wall!’ and they go nuts.”

Leading up to and during the 34-day government shutdown, Mr. Trump was more specific still, suggesting that Mexico would effectively be paying for the wall because of the money saved by the renegotiation of the North American Free Trade Agreement. (The New York Times found no evidence to support this claim.)

Examples of Mr. Trump’s characterizations of how Mexico would pay for the wall

In recent days, Mr. Trump has talked less about “building” a wall and more about “finishing” a wall. At a rally in El Paso on Monday, Mr. Trump struck an unyielding note: “We need the wall, and it has to be built.”

Other than “a wall,” what has Mr. Trump called his proposed border barrier with Mexico?

Barrier

Fence

Whatever you want/Doesn’t matter what it’s called

As a candidate, Mr. Trump rarely strayed from calling his proposed physical barrier anything other than a “wall” or a “great wall.” When he mentioned other names, like "fence," it was usually to highlight what he viewed as the weaker plans of skeptics or opponents.

That changed leading up to and during the shutdown. The wall is not popular among Americans, and it is especially unpopular among Democrats. Mr. Trump started using words like “fence” and “barrier,” which he had avoided as a candidate. Later, he began telling Democrats he didn’t care what it was called.

How Mr. Trump has characterized what else to call the wall besides a “wall”

Mr. Trump’s preferred term for the border barrier is still, simply, “the wall.” Even as lawmakers appeared to agree “in principle” about a deal that would avoid a shutdown, Mr. Trump said, “Just so you know, we’re building the wall anyway.”

What is it made of, or what are some of its physical characteristics?

Has a “beautiful door”

Concrete

See-through or transparent

Steel

The Times identified very few instances in which Mr. Trump was specific about the wall’s physical characteristics. Even its potential height — occasionally said to be somewhere between 35 feet and 50 feet — was mentioned rarely.

Some of the earliest details that Mr. Trump did mention: The wall would have a “beautiful door,” to make sure people crossing the border did so legally. To the extent that he did discuss its composition as a candidate, he usually said his wall would be made of concrete or “precast.”

The physical characteristics of Mr. Trump’s wall

Later, he began describing transparency — the ability to see through the wall — as a design requirement, using terms like “see-through” and “slats.” About a year later, amid the shutdown and negotiations about how to end it, Mr. Trump described the wall as made of American steel:

“Only a wall, or steel barrier, will keep us safe!”