The American English used in the country in terms of pronunciation and tonality has been referred described as an “American accent”. It conceptually is not like others forms of English for instance the Australian or the British English for it has a considerable proportion of soocial and spatial variation yet has some attributes in comparsion. You should remember that when the admiring speakers of English from other countries mention the ‘American accent,’ it can mean any of the many diverse variations of the dialect that is used throughout the country. An individual accent could even speak of the origin, this social class and the culture of the person. 

The term "General American" (often abbreviated as "GenAm") was first used in 1925 by descriptive linguist George Philip Krapp to characterize the accent that was gradually taking over in American English. People who have a distinctly American accent but are not from any one area of the country most likely have a general American accent. 

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One of Krapp's greatest works is Modern English: Its Growth and Present Use, which was first released in 1909.The book examines how the English language changed from Old English to Middle English to Modern English, highlighting changes in vocabulary, grammar, and pronunciation along with the forces that shaped those changes. 

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‍Like all linguistic components, the general American accent has changed throughout time. In comparison to older generations in the same region, younger generations in some places, like Pittsburgh, are exhibiting a trend of speaking with a general American accent. In the relatively near future, it is possible—if not likely—that Pittsburg and other areas will be grouped with the rest of North America.

Additionally, there are some areas that closely, if not exactly, mimic the pronunciations of the General American accent. For instance, the pronunciations of most Canadian speakers are strikingly similar to those of General Americans. Even though they are different in that Canadians usually raise their vowels, many people would not distinguish the difference in everyday speech.