During the early half of the 20th century, Mid-Atlantic classroom speech was designed, codified, and advocated by certain phoneticians and teachers, linguistic prescriptivists who felt that it was the best or most proper way to speak English.
[8][7][9] According to voice and drama professor Dudley Knight, "its earliest advocates bragged that its chief quality was that no Americans actually spoke it unless educated to do so".
[9] During the period when Mid-Atlantic accents acquired cachet within the American entertainment industry, certain stage and film actors performed them in classical works or when undertaking serious, formal, or upper-class roles,[10] while others adopted them more permanently in their public lives.
A study by linguist William Labov and others describes that non-rhoticity, "as a characteristic of British Received Pronunciation, was also taught as a model of correct, international English by schools of speech, acting, and elocution in the United States up to the end of World War II.
[17] Linguist Geoff Lindsey argues that another major contribution to the RP elements in early Hollywood sound films is actual actors from around the British Commonwealth.
[21] Linguistic prescriptivists, Tilly and his adherents emphatically promoted World English, and its slight variations taught in classes of theatre and oratory, helping to eventually define the Mid-Atlantic pronunciation of American classical actors for decades.
The popularity of a Mid-Atlantic accent in theatrical training is credited to several of his disciples, among them Windsor Daggett, Margaret Prendergast McLean, and Edith Warman Skinner.
[26] Margaret Prendergast McLean from Colorado became one of the most influential speech teachers for East Coast actors by the late 1920s, distinguished for her work at Boston's Leland Powers School and New York's American Laboratory Theatre.
[28] Canadian-born Edith Skinner, brought to the Laboratory Theatre by McLean, rose to prominence by the 1930s,[9][12][2] best known for her own instructional text Speak with Distinction, published in 1942.
[38] Alexander Scourby was an American stage, film, and voice actor who continues to be well known for his recording of the entire King James Bible completed in 1953.
Scourby was often employed as a voice actor and narrator in advertisements and in media put out by the National Geographic Society with his refined Mid-Atlantic accent considered desirable for such roles.
Codified versions of the Mid-Atlantic accent for the American theatre were published by voice coaches like Margaret Prendergast McLean and Edith Skinner ("Good Speech" as she called it).