Donald Trump is still figuring out the art of the non-apology apology.

After more than a year of refusing to budge as he moved from one firestorm to the next, the Republican nominee surprised everyone Thursday night by declaring that he lives with some “regret.”

But while he expressed remorse for the first time since getting into the presidential race 14 months ago, he steered clear of the S-word: “sorry.”

Parsing the speech, which was read from a teleprompter, veteran campaign strategists and historians noted that Trump sounded much more like a conventional politician than he has all year. In their view, he’s following a path of rhetorical evasion that has been well trod by candidates in both parties.

Linguists and relationship experts, meanwhile, said Trump’s comments were ineffective and that his words cannot accurately be described as an “apology.” In fact, the GOP nominee did not specify exactly who or what he was talking about. The targets over the course of his campaign are plentiful, including the parents of Capt. Humayun Khan, Sen. John McCain (R-Ariz.), Megyn Kelly, New York Times reporter Serge Kovaleski, Mexicans and Muslims.

At a rally in Charlotte, N.C., Republican presidential nominee Donald Trump said on Thursday that sometimes he hasn't chosen the right words to say and said that he regretted causing "personal pain." (The Washington Post)

Yet with his poll numbers sinking with 81 days left to go, Trump has finally decided to participate in a familiar ritual of penitence: asking the voters for grace after a headline-grabbing misdeed (or, in Trump’s case, many). It’s the same kind of public plea for forgiveness that U.S. Olympic swimmer Ryan Lochte also issued on Friday over revelations that he fabricated a story about being robbed in Rio (he didn’t actually use the word “sorry” either). But there are many celebrities (actor Mel Gibson after his drunken tirade against “the Jews”) and politicians (then-South Carolina Gov. Mark Sanford (R) after “hiking the Appalachian Trail”) who have been through it before.

Democratic nominee Hillary Clinton has also had to make some public mea culpas in her political lifetime — most recently, saying she was “sorry” for her use of a private email server as secretary of state.

Sometimes the public plea for forgiveness works; sometimes it doesn’t.

The biggest problem for Trump, experts said, was the vague nature of his actual words.

“Sometimes in the heat of debate, and speaking on a multitude of issues, you don’t choose the right words or you say the wrong thing. I have done that,” Trump said. “And believe it or not, I regret it. I do regret it, particularly where it may have caused personal pain.”

Asked if he’ll apologize to the Khan family, newly installed campaign manager Kellyanne Conway said “he may.”

“I certainly hope they heard him,” Conway said on ABC’s “Good Morning America.” “I hope that everybody who has criticized him at some point, for being insensitive or for mocking someone, at least shows some recognition and some forgiveness.”

New York University historian Tim Naftali, who previously directed the Richard Nixon presidential library, heard Nixonian echoes as he watched the tape of Trump’s speech in Charlotte on Thursday night. Two men who Trump talks to — Roger Ailes and Roger Stone — worked for the former president.

After Watergate, Nixon never apologized for breaking the law, even in his famous interview with David Frost. He instead said that he was sorry for causing the American people pain and suffering.

“An apology involves contrition. Neither Trump, so far, nor Nixon showed real contrition,” Naftali said. “Nixon, at least, believed apologies were a sign of weakness, which exposed him to more attacks from his real and perceived enemies.”

Trump’s insults have come fast and furious during the campaign, but he has never before apologized. “I don’t have regrets,” he said in March when asked about the charged rhetoric at his rallies.

After Khan’s father said Trump does not understand what “sacrifice” means during the Democratic National Convention, the GOP nominee spent a week attacking him. Even following heavy criticism of his attacks on a Gold Star family, Trump told WJLA: “I don’t regret anything.”

Susan Wise Bauer, who wrote the “The Art of the Public Grovel,” called Trump’s language about regret “pretty pathetic.”

“ ‘Regret’ is about the weaseliest non-apology, non-confession word you can pick,” said Bauer, who teaches American literature at the College of William and Mary. “You could ‘regret’ the fact it’s raining outside and have nothing to do with it.”

Perhaps that’s exactly why so many public figures use the word so often, in lieu of more direct words like “apologize” or “sorry.”

Last month, under fire for disparaging Trump as a member of the Supreme Court, Justice Ruth Bader Ginsburg said: “On reflection, my recent remarks ... were ill-advised and I regret making them.”

In 2008, after Joseph R. Biden Jr. called Barack Obama, at that point his opponent for the Democratic nomination, “the first sort of mainstream African American who is articulate and bright and clean and a nice-looking guy,” the Delaware senator released a statement saying: “I deeply regret any offense my remark ... might have caused anyone.”

For others, Trump’s non-apology recalled then-Oregon Sen. Bob Packwood’s mealy-mouthed response to sexual harassment accusations. “I’m apologizing for the conduct that it was alleged that I did, and I say I am sorry,” Packwood said in 1992.

“Trump’s not really able to name what he did wrong,” said Edwin Battistella, author of “Sorry About That: The Language of Public Apology” and a linguistics professor at Southern Oregon University. “If you think about what a good apology is, you really want to name what you did wrong and apologize specifically for that — not just say I’m sorry for ‘whatever.’ ”

Naftali says Trump is “testing the waters” to see if unspecified regrets is enough.

“That’s a classic way for an unrepentant person to try to get us to move on,” Naftali said. “What was unusual and new about what Trump did was that he actually took responsibility for the power of his words.”

Lauren Bloom, who wrote “Art of the Apology: How, When, and Why to Give and Accept Apologies,” said sincerity is a fundamental apology requirement. “I’m sure he sincerely regrets creating controversy that hurt his poll numbers, but that’s not being sorry,” she said.

Bloom argued that, if Trump was sincere, he would telephone some of the people he lashed into, including McCain (who he blasted for being captured in Vietnam) or Carly Fiorina (whose face he mocked).

But Republican strategists lack confidence that Trump has the self-discipline to stick with this approach.

“The speech was him trying yet again to send the same message — ‘we’re going to pivot’ — which we’ve seen for well over a year now is meaningless,” said Doug Heye, a former Republican National Committee communications director.

Besides her email server, Clinton has offered many non-apology apologies of her own. She defended her support for the Iraq War in 2008 before saying it was a “mistake” in 2014.

Bill Clinton is much more accomplished in the art of the non-apology apology. In April, he lectured Black Lives Matter protesters about his crime bill, angering some African Americans.

“I almost want to apologize,” he said the next morning.

But he did not. He just kept talking.