Recently a friend of mine was bemoaning the idiosyncratic differences between British English and American English on her blog. Rather than respond again to her post, I decided to write my own blog post in response to hers.
First, I would like to address the title of her own blog post. Why don’t Americans speak English? Well, we do. We just speak a different version of it. Just like Canadians and Australians do. There are words they use which are different to both British and American usage, yet no one asks why Australians don’t speak English. French and Spanish are the same way. Language, as you well know, is a constantly morphing entity. It’s fluid and changes not only with time, but with geography.
Second, in your writing you mention our use of sidewalk when you use footpath. I couldn’t find much etymology on the word sidewalk, other than it’s been around since 1739. I looked it up on Wikipedia as well and while there isn’t much further etymological information there, it does state that the more common usage in the UK for a walkway along a roadway is pavement, rather than footpath. The Wikipedia article states that the use of the word footpath is to refer to an area for pedestrian traffic where there is no roadway (or, in your case, carriageway) involved. I have heard people around here use the word pavement in lieu of sidewalk, but yes, by and large, Americans do refer to it as a sidewalk.
Third, as I know the whole point of this is the differences between British and American English, I decided to investigate more since we have many differences in the way we spell the same words. I think the Wikipedia article American and British English spelling differences does a smashing job at breaking down the differences. You might be surprised to know that there are a lot more acceptable spellings of words that are “our” versions vs. yours. Of course I’m sure you’ll debate the validity of the claims made by an article on Wikipedia as everyone does.
Ultimately, though, it boils down to one man – Noah Webster – who believed strongly in English-language spelling reform. His dictionary is what our spelling is based on, while, generally, yours is based on one compiled by Samuel Johnson.