Experts in Scotland have begun to unravel the mysteries of the unique Kiwi accent, according to a new study.

Academics have discovered that New Zealand English is one quarter Scottish, one quarter Irish and 50% cockney/northern/west country English.

Linguists have long been baffled by how New Zealanders all came to speak in one distinctive English dialect, so that the iconic British dish of "fish and chips" is pronounced "fush and chups", "seven" is "siven" and vowels are raised in words such as "dress" and "trap".

Now scientists are helping linguists solve the conundrum of the dialect spoken by the likes of Hollywood actor Russell Crowe and soprano Dame Kiri Te Kanawa.

It had previously been suggested that Australian English is "exported Cockney" and that New Zealand English is derivative of Australian.

But physicists and mathematicians, working with language experts, believe they understand why the dialect developed so quickly and uniformly across New Zealand - so that just 50 years after the arrival of British settlers in the 1850s most New Zealanders spoke the same dialect.

Physicists from Edinburgh and Manchester universities - working with mathematicians from New Zealand and linguists from the US - suggest improved transport links within the country, coupled with the growth of a class system, appeared to contribute to the emergence of the dialect.

The five-year study confirms that the dialect came from the mother country, Britain.

Dr Richard Blythe, a physicist from Edinburgh University, said: "Most of the immigrants to New Zealand came from the British Isles in the 1850s, and they all landed with British regional dialects."

He said that, while the first generation of immigrants did little to change their dialects, their children started to adapt their speech in a way not yet properly understood.

"Scots had quite a bit of influence. They are said to have had a particular role as teachers in New Zealand, so this would have had some effect on the children."Dr Blythe believes that being a physicist gave him a different perspective on how linguistic changes could move through a population.

"We can never really predict what one person might do. What we can do is predict what might happen in the population as a whole. It's that mindset driving our work," he said.

The researchers analysed material, including radio interviews with New Zealand's oldest inhabitants, and used a mathematical model to trace language changes.

At the time the Kiwi dialect was born, there would have been from 100,000 to one million people in New Zealand. The team applied the same mathematics to model what happened as is used to deduce the overall properties of a gas from its constituent molecules.

The first wave of settlers arrived on ships from Glasgow, London, and Plymouth and the rough proportions of English, Scots and Irish were 50%, 27% and 23%.

But within the English group there were a range of dialects, from London, the south-east, the south-west and Lancashire. The same sound used in several dialects could form a majority, concluded the study, and this is the variant most likely used today.

"Australian English was formed in a similar way - that is, by dialect mixture," added Dr Blythe.