Rhoticity is common in most American accents despite being now rare in England because, during the 17th-century British colonization of the Americas, nearly all dialects of English were rhotic, and most of North American English simply remained that way. The preservation of rhoticity in North America was also supported by continuing waves of rhotic-accented Scotch-Irish immigrants, most intensely during the 18th century (and moderately during the following two centuries) when this ethnic group eventually made up one-seventh of the colonial population. Scotch-Irish settlers spread from Delaware and Pennsylvania throughout the larger Mid-Atlantic region, the inland regions of both the South and North, and throughout the West: American dialect areas that were all uninfluenced by upper-class non-rhoticity and that consequently have remained consistently rhotic.Wolfram, Walt; Schilling, Natalie (2015). American English: Dialects and Variation. John Wiley & Sons. pp. 103–104. While non-rhoticity spread on the East Coast (perhaps first in imitation of early 19th-century London speech), even the East Coast has gradually begun to restore rhoticity, due to it becoming nationally prestigious since the mid-20th century. The pronunciation of is a postalveolar approximant or retroflex approximant , but a unique "bunched tongue" variant of the approximant r sound is also associated with the United States, perhaps mostly in the Midwest and the South.
rhoticity is common in most american accents despite being now rare in england because during the 17th-century british colonization of the americas nearly all dialects of english were rhotic and most of north american english simply remained that way the preservation of rhoticity in north america was also supported by continuing waves of rhotic-accented scotch-irish immigrants most intensely during the 18th century (and moderately during the following two centuries) when this ethnic group eventually made up one-seventh of the colonial population scotch-irish settlers spread from delaware and pennsylvania throughout the larger mid-atlantic region the inland regions of both the south and north and throughout the west american dialect areas that were all uninfluenced by upper-class non-rhoticity and that consequently have remained consistently rhoticwolfram walt; schilling natalie (2015) american english dialects and variation john wiley & sons pp 103–104 while non-rhoticity spread on the east coast (perhaps first in imitation of early 19th-century london speech) even the east coast has gradually begun to restore rhoticity due to it becoming nationally prestigious since the mid-20th century the pronunciation of is a postalveolar approximant or retroflex approximant  but a unique "bunched tongue" variant of the approximant r sound is also associated with the united states perhaps mostly in the midwest and the south