The course did not drop all at once. Salvat employed the "partwork" model, which was genius for cash flow and engagement:
: A recurring figure used to teach daily routines, such as getting up at 5:00 AM and eating breakfast at 6:00 AM. Vocabulary Lessons salvat ingles bbc english course 1976 1978
Why was this course so trusted? The acronym BBC . In the 1970s, the BBC was not just a broadcaster; it was a global symbol of educational authority. The English spoken by BBC announcers was considered the "correct" English—the Queen’s English, devoid of regional slang or Americanisms. The course did not drop all at once
: Approximately 9 to 24 cassettes featuring native British speakers performing dialogues and drills. salvat ingles bbc english course 1976 1978