Why Do Americans and Brits Have Different Accents?
In 1776, whether you were declaring America independent from the crown or swearing your loyalty to King George III, your pronunciation would have been much the same. At that time, American and British accents hadn’t yet perged. What’s surprising, though, is that Hollywood cosplaytume dramas get it all wrong: The Patriots and the Redcoats spoke with accents that were much closer to the contemporary American accent than to the Queen’s English.
It is the standard British accent that has drastically changed in the past two centuries, while the typical American accent has changed only subtly.
Traditional English, whether spoken in the British Isles or the American colonies, was largely "rhotic." Rhotic speakers pronounce the "R" sound in such words as "hard" and "winter," while non-rhotic speakers do not. Today, however, non-rhotic speech is common throughout most of Britain. For example, most modern Brits would tell you it’s been a "hahd wintuh."
传统英语，无论是在英伦三岛或美国殖民地，其发音大多数都带有“卷舌音” 。带卷舌音的人在说 "hard（艰难）" 和 "winter（冬天）" 这种词时，一直发出“R”音，而不带卷舌音的人则不然。然而今天，在英国大多数区域，大家说话一般都不带卷舌音。比如，大多数目前英国人会告诉你，这是一个“hahd wintuh（严冬）”。
It was around the time of the American Revolution that non-rhotic speech came into use among the upper class in southern England, in and around London. According to John Algeo in "The Cambridge History of the English Language" (Cambridge University Press, 2001), this shift occurred because people of low birth rank who had become wealthy during the Industrial Revolution were seeking ways to distinguishthemselves from other commoners; they cultivated the prestigious non-rhotic pronunciation in order to demonstrate their new upper-class status.
"London pronunciation became the prerogative of a new breed of specialists — orthoepists and teachers of elocution. The orthoepists decided upon correct pronunciations, compiled pronouncing dictionaries and, in private and expensive tutoring sessions, drilled enterprising citizens in fashionable articulation," Algeo wrote.
The lofty manner of speech developed by these specialists gradually became standardized — it is officially called "Received Pronunciation" — and it spread across Britain. However, people in the north of England, Scotland and Ireland have largely maintained their traditional rhotic accents.
由这类专家们开发的高傲讲话方法渐渐成为标准化 -被正式称为“标准发音” -在英国各地传播开来。不过，在英格兰北部、苏格兰和爱尔兰的大家大多数都还维持其传统带卷舌音的口音。
Most American accents have also remained rhotic, with some exceptions: New York and Boston accents have become non-rhotic. According to Algeo, after the Revolutionary War, these cities were "under the strongest influence by the British elite."