Democratic Presidential candidate and former US vice president Joe Biden used a phrase during Tuesday night's chaotic first presidential debate that is all too familiar to speakers of the Arabic language and Muslim households but could hardly be expected to be heard in a nationally televised American debate: Inshallah.

Biden used the word — meaning 'God willing' in Arabic and Farsi — as Republican President Donald Trump hedged on saying when he would release his tax returns.

“Millions of dollars and you’ll get to see it,” Trump said of the amount he claims to have paid, according to The Washington Post.

“When?” the Democratic presidential candidate interjected. “Inshallah?”

The use of one of the most ubiquitous phrases in Arabic by gaffe-prone Biden, 77, a Roman Catholic, raised eyebrows in the Mideast and migrant communities, with many debating the contextual meaning of the phrase.

Al-Arabiya, a Saudi-owned satellite channel based in Dubai, and The National, a state-linked newspaper in Abu Dhabi, both published articles noting Biden's use of the word.

Others questioned whether Biden had used the word at all. The former vice president has battled a stutter and is known for sometimes tripping over his words, so many viewers were left wondering if he had actually said “under the law?” or “In July?” or even “Enchilada?”

However, the Democratic nominee's campaign confirmed to NPR that he had, in fact, used the phrase.

Besides its literal meaning of God willing, Inshallah can also be used in a way to suggest something won't ever happen. Writer Wajahat Ali called this interpretation of the word the “Arabic version of ‘fuggedaboudit (forget about it)’.”

Fadi Hilani, a linguistics professor at Montclair State University in New Jersey who has researched the use of “Inshallah”, told The Washington Post it was clear Biden used the word sarcastically and uttered it with a slight smirk.

“He was casting doubt, in a sarcastic way, on Donald Trump saying he would release his tax returns,” he said. “What Trump is saying is too good to be true.”

During the course of the rancorous first debate marked by personal insults, name-calling and Trump’s repeated interruptions, the US president and Biden battled fiercely over Trump’s leadership on the coronavirus pandemic, the economy and the integrity of November’s election.

Moderator Chris Wallace never established control of the debate. The two White House contenders talked over each other and lobbed insults in a breathtaking political brawl that made it hard for either to make a point.

Biden, 77, has held a consistent lead over Trump, 74, in national opinion polls, although surveys in the battleground states that will decide the election show a closer contest. It was hard to determine whether the debate would move the needle.