> The longest Oscar speech was given by Greer Garson at the 15th Academy Awards after she was named Best Actress for 1942 for Mrs. Miniver. Her speech ran for nearly six minutes.[11] It was shortly after this incident that the academy set forty-five seconds as the allotted time for an acceptance speech and began to cut the winners off after this time limit.
https://en.wikipedia.org/wiki/Oscar_speech
There's no citation for that claim though and I can't find anything definitive, but here's Denzel Washington referencing the limit in 1990:
https://aaspeechesdb.oscars.org/link/062-2/
Here's an article from 2001 referencing the 45-second limit again:
https://abcnews.go.com/Entertainment/story?id=108258
It seems like there's news articles every year claiming the limit is a new thing. Here's an article from 2010:
https://www.theguardian.com/film/2010/feb/16/oscar-winners-s...
(Linked from the original article, but clearly the 45-second limit predated 2010.)
Regardless of when the limit first appeared, the orchestra did attempt to hurry Brody along after he was several minutes into his speech and well over 45 seconds:
https://www.americanrhetoric.com/speeches/adrienbrodyoscarsp...