Claims the Australian accent sounds slurred because our forefathers were drunk all the time are "absolute rubbish", an expert says.

Victoria University public speaking expert Dean Frankel claims the Australian alphabet was "spiked by alcohol" because the first British arrivals to the country were big drinkers.

Mr Frankel told the ABC "speech was more contagious than the flu" and said: "Clearly we have been sloshed in alcohol for a very long time".

He said frequently drunk interactions between early settlers unknowingly added an alcoholic slur to our national speech patterns, and that speech continued to be taught by sober parents to their children.

"Alcohol to Australians is like guns to Americans," Mr Frankel said. "Alcohol has been a part of the Australian culture for so damn long, it is crucial to the DNA of Australia."

But UQ linguistics expert Dr Rob Pensalfini described the theory as an example of "cultural cringe" and "absolute rubbish".

Dr Pensalfini said theories like Mr Frankel's were often advanced for all kinds of accents, and were commonly unfounded.

"They say New Yorkers have nasal voices because they have to cut through the noise of the traffic," he told the ABC.

"The original one for Australia was we speak in a slurred and closed-lip way to keep the flies out of their mouths.

"They're all completely baseless ... I want to see the evidence, I want to see the instrumental valuations."

He said standard Australian language came from mostly Cockney origins with an influence of Irish-English.

"There are some parts of Australia with other influences ... in high density areas, especially in Sydney and Melbourne, there is some urban, sometimes called wog speak, also known as new Australian English.

Dr Pensalfini, who is also an actor and director, added drunks often in fact over-articulated rather than slurred their words because they were "aware of their impairment".

"That's a cliche too, but if I was coaching an actor to be drunk I would tell them to ... very deliberately say what they've got to say."

Aussie only using two-thirds of their speech 'toolkit'

Mr Frankel said Australians only spoke at two-thirds of their capacity, using just part of their "toolkit".

"The Australian alphabet is 23 letters long. 'L' is one of those missing," he said.

"A lot of us find it hard to use 'l' at least in the middle of words. We use a 'w' in that."

He said people have four groups of articulate muscles that enabled them to turn vocal sounds into words, and not everyone used them.

"If you put a drunk person next to someone who isn't drunk, but who has a very heavy Australia accent, often you will not be able to tell the difference," Mr Frankel said.

He said communications should be compulsory in the Australian school curriculum, helping the nation to become a "cleverer country".

Bad communication was costing Australia billions, holding back the growth of emotional intelligence and contributing to mental health issues and domestic violence, Mr Frankel said.

"We might have less domestic violence if we were taught to communicate better."

He said people needed to adopt a broader vocabulary to better express themselves, and stop relying on alcohol to open up.

"Many Australians are not very good at expressing themselves unless they've had a bit of turp.

"They hold onto their emotions then it only comes out when they've had enough to drink."

Listen to a Radio National interview with Dean Frankell.