Donald Trump uses the phone and puts his sock-covered feet on the table in his private plane as he flies to Minnesota Associated Press President-elect Donald Trump has spoken to dozens of foreign leaders on the phone since he won the election.

The calls have been somewhat unorthodox.

Trump spoke with President Tsai Ing-wen of Taiwan last week, sparking an uproar considering it marked the first time a US president has directly spoken with Taiwan's leadership in more than 30 years.

Some experts worried the move could strain US relations with China. The US suspended formal diplomatic relations with Taiwan in 1979 after establishing a One China position in an effort to establish diplomatic channels with Beijing.

Around the same time, Trump spoke to the leaders of Pakistan, Kazakhstan, and the Philippines, and those countries released readouts that were striking in their detail and candor.

Here's an overview of how Trump is shaking up diplomacy with his post-election interactions with foreign leaders.

Taiwan's President Tsai Ing-wen speaks during an interview in Luque Thomson Reuters

Taiwan

The call between Trump and Ing-wen was reportedly months in the making.

Ian Bremmer, a geopolitical expert and president of the Eurasia Group, said Beijing would be "absolutely incensed" about the call.

He noted that the call ignored protocol. The White House said it didn't know about the call until after it occurred.

"Trump is just taking all sorts of calls of congratulations and has ignored both protocol and intel briefings," Bremmer told Business Insider in an email last week. "This is his first serious misstep accordingly. We'll surely see more."

He continued: "Inconceivable the Chinese won't react harshly to this. This is a red line for them. And hard to imagine Trump saying 'no big deal' and not talking to the Taiwanese going forward. We are now stuck [with] escalation, and US-China relations under Trump get off to a particularly ugly start."

Beijing views Taiwan as a province of China, whereas Taiwan — which has its own democratically elected government — has a more complicated view of the nations' relationship.

Philippine President Rodrigo Duterte, left, listens to Russian President Vladimir Putin during their meeting at the Asia-Pacific Economic Cooperation (APEC) forum in Lima, Peru, November 19, 2016. Mikhail Klimentyev, Sputnik, Kremlin Pool Photo via AP

Philippines

Philippine President Rodrigo Duterte, the notoriously foul-mouthed leader who called President Barack Obama a "son of a whore" earlier this year, also spoke to Trump.

The call came after Duterte announced his "separation" from the US and declared his realignment with China. He also threatened to draw closer to Russia, a country Trump has also cozied up to.

Trump and Duterte spoke earlier this month by phone. At a UN Convention Against Corruption conference in Manila this week, Duterte shared a profanity-laced version of their seven-minute conversation, quoting Trump as saying the US and the Philippines "should fix our bad relations."

"It needs a lot of ... you know, you just said something good here, and you're doing great," Duterte quoted Trump as saying. "I know what you're ... you worry about Americans criticizing you. You're doing good, go ahead. I had this problem in the border of Mexico and America."

Duterte has a reputation for human-rights abuses and extrajudicial killings.

He also said Trump invited him to visit the US.

"Oh yes, when you come to Washington, DC, or New York City, look me up and I will have coffee," Deterte quoted Trump as saying. "Maybe you can give me a suggestion, one or two, how to solve this goddamn bulls---."

Pakistan's Prime Minister Nawaz Sharif, right, meets Indian counterpart Narendra Modi in Lahore, Pakistan, Friday, Dec. 25, 2015. Press Information Department via AP

Pakistan

Trump also had words of praise for Pakistan Prime Minister Nawaz Sharif.

Pakistan's government released a detailed readout of the call, saying Trump praised Sharif as a "terrific guy" and called Pakistanis "one of the most intelligent people."

Sharif apparently called Trump to congratulate him on winning the White House, and Trump responded by speaking approvingly of Sharif's "very good reputation."

"You are doing very good work which is visible in every way," Trump said to Sharif, according to the readout. "I am looking forward to [seeing] you soon."

Sharif and his family were caught in a corruption scandal amid the release of the Panama Papers, and the embattled prime minister is facing increasing uncertainty among the public about his rule.

Some also wondered what Trump's praise would mean for US relations with India, which has a tense relationship with Pakistan.

Alyssa Ayres, a senior fellow for India, Pakistan, and South Asia at the Council on Foreign Relations, said the Pakistani readout "a level of detail that you normally don't see." But she said that she recently returned from India and she doesn't "think anybody in India is seriously worrying about this."

"I've never seen a readout like that," Ayres told Business Insider. "Normally you agree on the counters of the readout in advance. I think you see the fact that Trump is carrying out this phone call diplomacy without coordinating with the State Department."

She said Hillary Clinton, the former US secretary of state and Democratic nominee for president, "would have been much more careful about that particular situation."

Ayres speculated that Trump, who has experience dealing with international businessmen, has gotten used to these kinds of interactions.

"I do think he probably having spent an entire career in international business and in property development and TV and entertainment, he's become accustomed to putting a really positive face forward and providing praise where needed," she said.

Nazarbayev, President of Kazakhstan waits to address attendees during the 70th session of the United Nations General Assembly at the U.N. headquarters in New York Thomson Reuters

Kazakhstan

Trump also spoke to Kazakhstan President Nursultan Nazarbayev, the former first secretary of the country's communist party.

Kazakhstan has become an increasingly authoritarian country, and Nazarbayev has been accused of restricting the press and rigging elections.

The Kazakh government's readout of Nazarbayev's phone call with Trump mirrored Pakistan's in its detail, candor, and language.

"The US President-elect brought congratulations to the Head of State on the 25th anniversary of Kazakhstan's Independence," the press release said. "D.Trump stressed that under the leadership of Nursultan Nazarbayev our country over the years of Independence had achieved fantastic success that can be called a 'miracle.'"

The release also declared that Trump and Nazarbayev "declared determination of taking friendly Kazakhstan-American relations to a new level, including trade and economic partnership." Trump also reportedly expressed interest in arranging a meeting with Nazarbayev.