That's a false fact.
And it's apparent, since there are dozens of accents in the US as well as umin the UK and there were dozens in the UK 200 years ago. They all developed in their own direction, being sometimes isolated sometimes cross-pollinating with other accents, but none staid the same.
I’ve been believing this for a very long time but I’ve seen a video made by a French Canadian that proved me wrong
As a matter of fact, when first immigrants arrived in Nova Scotia, most of the French people weren’t even speaking French, but regional dialects.
What happened is that immigrants had to spend long periods of time in big ports of France before taking the boat to the new World and this is how they learned to speak French.
But English was the language mainly used for trades, and local French speakers included a lot of English words in their daily dictionary (which were then exported to France)
Then England took control of Canada and tried to eradicate the French spoken there because they thought it was impure and perverted.
French speakers were pissed, and began to protect the language with tough anti-English rules
Language, religion, and laws. This is why Quebec is predominantly French, doesn't use British common law like America and the rest of Canada, and was predominantly catholic at a time when a lot of places required you to follow the king's (or queen's) religion.
And why a Catholic school board exists in the entire country. We're far past the point it should be allowed to exist, but afaik it's in the constitution and hard to get rid of.
I'm responding to "tried to eradicate the French spoken there". When they took over, I'm pretty sure they agreed to the French language and Catholicism from the very beginning. They didn't try to eradicate it. Protection didn't come from failed eradication attempts, protection was agreed to from the start.