Summary

Portrait of H. L. Mencken H. L. Mencken The American Language — Vulgar Pronunciation (1919)

No single investigator can examine the speech of the whole country; for that business a pooling of forces is necessary. But meanwhile it may be of interest to set forth a few provisional ideas.
At the start two streams of influence upon vulgar American pronunciation may be noted, the one an inheritance from the English of the colonists, and the other arising spontaneously within the country, and apparently much colored by immigration. The first influence, it goes without saying, is gradually dying out. Consider, for example, the pronunciation of the diphthong oi.
Source: Wikisource

Portrait of H. L. Mencken H. L. Mencken The American Language — Vulgar Pronunciation (1919)

England has gone back to the broad a, but in America the flat a persists, and many Americans who use sassy every day would scarcely recognize saucy if they heard it. Yet again, there is quoit. Originally, the English pronounced it quate, but now they pronounce the diphthong as in doily. In the United States the quate pronunciation remains. Finally, there is deaf. Its proper pronunciation, in the England that the colonists left, was deef, but it now rhymes with Jeff.
Source: Wikisource

Portrait of H. L. Mencken H. L. Mencken The American Language — Vulgar Pronunciation (1919)

An unlearned American, wishing to say that he was enraged, never says that he was roiled, but always that he was riled. Desiring to examine the hoof of his horse, he never orders the animal to hoist but always to hist. In the form of booze-hister the latter is almost in good usage. I have seen booze-hister thus spelled and obviously to be thus pronounced, in an editorial article in the American Issue, organ of the Anti-Saloon League of America. [2]
Various similar misplaced vowels were brought from England by the colonists and have persisted in America, while dying out of good English usage.
Source: Wikisource

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