Joe Biden is preparing to deliver one of the most important speeches of his life when he is inaugurated as the 46th President of the United States.

But one of Australia’s leading speech experts says he will be confronted with a challenge, that many people take for granted.

Speech pathologist and director of the Australian Stuttering Research Centre, Professor Mark Onslow, told 6PR’s Liam Bartlett, Biden will have to work extra hard on his speech because of his childhood stutter.

“Joe Biden is a wonderful inspiration to people who stutter because he has got it under control,” he said.

“But even today he has to exert a great deal of physical and mental energy to keep it under control.”

Biden overcame a speech impediment in his early years, after being bullied for his stutter.

The genetic impediment is a physical disorder that originates in the brain.

Professor Onslow told 6PR Mornings stuttering can be debilitating for many people.

“They have to think of the content, of what they are going to stay, and they can’t assume their speech mechanism is going to work,” he said.

“You need a hundred muscles to coordinate very quickly when you’re talking, and people who stutter have a slight problem with that coordination.”

Click play to hear the full interview. 

(Photo: The Washington Post /Getty Images.)