American English diverged from British English following colonial settlement in the 17th century, developing distinctive features through various influences. Noah Webster's "American Dictionary of the English Language" (1828) standardized American spelling (color vs colour, theater vs theatre). Regional dialects emerged from different settlement patterns: Southern American English, New England dialects, Midwestern English, and African American Vernacular English (AAVE). Immigration waves introduced vocabulary from Spanish, German, Italian, and other languages. The Great Vowel Shift had largely concluded before American colonization, meaning some features preserved older English pronunciations. What factors primarily contributed to American English developing as a distinct variety from British English?