There are really no Geographic feature per se. The is time and every thing impact ing the evolving local evolving cultures.
Linguist who touch on remote locales which have similar language patterns to Old English, Think Outerbanks Islands, Skye Island etc. Now the the English colonies in North America evolved differently than the the UK. Our language patterns differed consequently.
Now the lack off communications technology from the 16000's to lets say 1900 aided this process. Here is an example
To Table a subject
US = To defer to later
UK = let's deal with it now
And the list goes on