In 1776, both American accents and British accents were largely rhotic.

It was around this time that non-rhotic speech took off in southern England, especially among the upper class; this “prestige” non-rhotic speech was standardized, and has been spreading in Britain ever since.

Most American accents, however, remained rhotic.

There are a few fascinating exceptions: New York and New England accents became non-rhotic, perhaps because of the region’s British connections. Irish and Scottish accents are still rhotic.

Fascinating.