Accents: Which came first 'bath' or 'barth'?
It is the debate which has divided the north and south for years: "What is the right way to say bath?"
The short vowel version, the northern way, may not be "the right way", but it came first by a decent stretch.
But the vast differences between British accents go much deeper than the pronunciation of just one word.
From the Vikings invading to Geordie Shore, many things have influenced the way we speak, and will continue to do so.
Why we sound the way we do
Britain has been invaded several times by people speaking different languages.
Some parts were colonised by the Anglo-Saxons, who came from north-western Europe, the Vikings, who were from Scandinavia, and the Normans, who came from Normandy in Northern France. Other parts remained unconquered.
The Anglo-Saxons, the Normans and the Vikings settled in different parts where they learnt English and found their own style of speaking it, and because mobility was limited external influence on communities was rare.
Lecturer in Dialectology at Sheffield University, Chris Montgomery, says those different ways of speaking helped form the regional accents we know today.
He explains: "People in the north east don't speak with a Norwegian accent, but they do sound different to a Midlands accents, and that is due to settlement patterns."
Chris also tells Newsbeat another reason for a variation in accents is because certain areas have ports, which immigrants would use to enter the country and then tend to stay in the area where they arrived.
An example of this would be Liverpool, where over the centuries many Irish and Welsh immigrants settled in the city, not knowing they were helping to form the distinctive Scouse accent.
'Laff' or 'larf'?
If you hopped into a time machine and went back around 300 years, experts believe you would struggle to find someone who said the word laugh, pronounced "larf", anywhere in the UK.
However, soon after that it started to become trendy in London to lengthen the vowel sound in certain words like "laugh", so it sounded like "laaff".
Around a century later, Londoners took the pronunciations a step further, so "laugh" sounded like "larf".
This way of speaking spread out over southern England and stuck, but from south of Birmingham upwards, people kept with the traditional way of saying words like "laugh", "grass" and "bath", with a single "a".
What accent is the hardest to understand?
No accent is harder to understand than any another, it's more based on who you are and who you speak to.
Chris Montgomery says: "Lots of accents can be really hard to understand, if you encounter a really broad speaker of that accent.
"If you go to an unfamiliar location and meet a group of old men in a pub, you may struggle to understand them because they are in a relaxed environment, so may speak quicker, and they are older, so they may use more traditional speech.
"It tends to be older men that people struggle with the most, rather than any particular accent, because they generally retain more traditional accent features, which younger people may find more difficult to understand."
How are accents changing?
Accents are constantly evolving and changing, and as we become increasingly mobile, new accents are forming as people discover different ways of talking, and sometimes adopt it.
Ever improving verbal communication links, like Skype and FaceTime, are closing the gap between the north and south, and as a result many regional accents are thought to be softening and becoming less distinctive.
However, many cities and large towns are thought to still be managing to retain their individuality, helped by media coverage, celebrities with strong accents and TV shows like The Only Way Is Essex.
Other accents seem completely resistant to change, particularly (you guessed it) the Scouse accent.