Machines believe most Northerners sound alike irrespective of their hometown, a study has found.
A piece of research from the University of Manchester looked at the similarity of accents across the North of England and how distinguishable they are.
It found that apart from the most recognisable twangs — Geordies and Scousers — the voices of people from other major northern hubs are largely comparable.
Residents of Leeds and Manchester, from the historic rivals of Yorkshire and Lancashire, were almost indistinguishable from one another, the study found.
Some academics have stated that this may be a recent phenomenon caused by the gradual eroding of regional accents due to 'dialect levelling'.
This has led to a theory that many well-educated middle-class northerners speak with a similar accent, dubbed General Northern English.
'I often hear statements like "I'm from Liverpool / Manchester / Sheffield, but I don't have the accent" - however, there is very little systematic evidence that General Northern English really is a coherent variety, so that's the question we asked ourselves,' said Dr Dr Patrycja Strycharczuk.
Previous research has found significant differences in the accents of people from the North and the South of England.
For example, the good folk in the North of England use phrases such as 'give it me', which would never be uttered by a well-to-do member of the South.
Northerners have also created creative colloquialisms for boring words, such as 'ginnel' or 'jitty' for alley and 'spelk' for splinter in Newcastle.
However, these are not influenced by accent, which is categorised by linguistic experts as phonological or phonetic features.
The scientists in this latest study say this can be boiled down to the pronunciation of certain words, specifically 'trap', 'bath', 'foot' and 'strut'.
Some people in the South will say all these words in a certain way, but residents of southern city may say it differently.
However, in the North, there is no variation. No true Northerner says 'bath' with anything other than a short 'a', with the word rhyming with the female name Kath.
But in the South, some will pronounce the word so that it has an elongated 'a' sound, making it rhyme with hearth.
This trait helps experts define the Northern accent as being 'a cluster of distinct but related varieties', which are united by their distaste for speaking like Southerners.
A seminal study into this phenomenon, published in 1982, said: 'There are many educated northerners.. who would feel it to be a denial of their identity as northerners to say BATH words with anything other than a short 'a'.'
Dr Strycharczuk investigated if the clearly defined accents of yesteryear were still present.
She took 105 accents of natives from the Northern powerhouses of Sheffield, Liverpool, Newcastle, Manchester and Leeds.
These were then fed into a machine which scrutinised the pattern of their voices.
It found people from Leeds, Manchester and Sheffield sounded similar, only correctly identifying an accent 67, 63 and 55 per cent of the time, respectively.
But the residents of Liverpool and Newcastle were more easily spotted, being correctly identified 82 and 71 per cent of the time, respectively.
'This summary confirms that Liverpool and Newcastle are generally well-discriminated from the remaining cities, the researchers write in their study.
'In contrast, Leeds and Sheffield are highly confusable.'
The researchers found that some traditional dialect features are no longer present, but most speakers still sound distinctly northern.
This they said could be determined by the use of short vowels in words like 'glass' and 'grass' while 'crux' is pronounced in the same way as 'crooks'.
The data also confirms that many highly educated urban speakers in the North keep at least some northern vowels in their speech.
Dr Strycharczuk says: 'It may seem as though local accents are dying out, but we believe we're actually seeing a new variety becoming established - educated, urban and northern.
'I think its prestige has increased, and people are now less tempted to lose their accent if they've been to university or they do a lot of public speaking.'
The research has been published in the journal Frontiers in Artificial Intelligence.