Johnny Depp's real accent has left fans confused and concerned

For many tuning into the Depp v Heard defamation trial, this could be the first time they are hearing Johnny Depp's real voice and accent. And it has stirred quite some confusion.

After decades on-screen, Depp has brought dozens of characters to life, each with unique and remarkably accurate accents.

Perhaps, though, his most famous is the drunken British drawl he put on for Captain Jack Sparrow that had many convinced he actually was British.

He has also perfected a cockney accent as Sweeney Todd, Scottish for Finding Neverland, and a tongue-twisting Glaswegian accent as the Mad Hatter in Alice in Wonderland.

The man is a chameleon of Hollywood – funnily enough, he even voiced one in the 2011 animated flick Rango.

After voicing so many characters throughout his decades-long career, his "real" accent seems to have morphed into a European-American blend which, in the thick of a brutally public defamation trial, some critics have said is less than convincing.

It begs the question: what is Johnny Depp's real accent, and has his career made him forget how to speak "normally"?

What accent does Johnny Depp have?

Depp was born in Owensboro, Kentucky on June 9, 1963. He told Rolling Stone magazine he moved more than 40 times throughout his childhood.

When he was 7 his family settled in Miramar, Florida, where he lived until he dropped out of high school and relocated to Los Angeles to become a rock musician and, eventually, an actor.

Long story short, he (and at least his base accent) is as American as they come.

Has his accent changed?

Throughout his career, Depp has been accused of changing his accent or dipping in and out of British, Scottish, even dabbling in an Australian lilt every now and again.

During a promotional interview for his 2015 film Black Mass on NBC's Today Show, Depp warbled through a number of accents, including the Bostonian twang he donned while portraying gangster Whitey Bulger.

It appears that having to endlessly pick up different accents has had some impact on his way of speaking, as well as his lifestyle that has seen him travel around the world and live in a number of different countries.

Does he have a speech impediment?

Some have suggested Depp has a stutter, due to the manner he spoke through the trial.

He seemed to struggle to say certain phrases but this could be because he was uncomfortable talking about such a sensitive, traumatic subject matter in public.

It has also been speculated that Depp has developed Foreign Accent Syndrome (FAS) which, according to Marca, causes a sudden change to a person's speech that is perceived as a foreign accent.

Only about 100 people have ever been diagnosed with FAS, and the majority have developed as the result of a traumatic head injury, so it is unlikely Depp has it.

Critics are not convinced by his 'real' accent

American shock jock Howard Stern has criticised Depp for "overacting" during the defamation trial.

While discussing the trial on his SiriusXM radio show, Stern took aim at Depp's "difficulty in speaking the English language" and his accent.

"First of all, isn't he [Depp] from like the South of the Midwest? Johnny Depp was born in Kentucky. Does that sound like a guy from Kentucky?" Stern said.