The common use of the word "dialect" in the U.S. is illustrated by Mark Twain's use of the word in his introduction to "Huckleberry Finn:"
"In this book a number of dialects are used, to wit: the Missouri negro dialect; the extremest form of the backwoods Southwestern dialect; the ordinary 'Pike County' dialect; and four modified varieties of this last. The shadings have not been done in a haphazard fashion, or by guesswork; but painstakingly, and with the trustworthy guidance and support of personal familiarity with these several forms of speech.
I make this explanation for the reason that without it many readers would suppose that all these characters were trying to talk alike and not succeeding."
When younger children try to tackle "Huckleberry Finn," adults will often say "Oh, that's a hard book to read because of all the dialect in it."
“I see a light a-comin’ roun’ de p’int bymeby, so I wade’ in en shove’ a log ahead o’ me en swum more’n half way acrost de river, en got in ‘mongst de drift-wood, en kep’ my head down low, en kinder swum agin de current tell de raff come along. Den I swum to de stern uv it en tuck a-holt. It clouded up en ‘uz pooty dark for a little while. So I clumb up en laid down on de planks. De men ‘uz all ‘way yonder in de middle, whah de lantern wuz. De river wuz a-risin’, en dey wuz a good current; so I reck’n’d ‘at by fo’ in de mawnin’ I’d be twenty-five mile down de river, en den I’d slip in jis b’fo’ daylight en swim asho’, en take to de woods on de Illinois side."