https://news.uga.edu/classic-georgia-accent-fading-fast/

A collaborative study between the University of
Georgia and Georgia Tech has found the classic
Southern accent is undergoing rapid change in
Georgia. The instigator? Generation X.

“We found that, here in Georgia, white English
speakers’ accents have been shifting away from
the traditional Southern pronunciation for the
last few generations,” said Margaret Renwick,
associate professor in UGA’s Franklin College
of Arts and Sciences department of linguistics
and lead on the study. “Today’s college students
don’t sound like their parents, who didn’t sound
like their own parents.”

The researchers observed the most notable change
between the baby boomer generation (born 1943 to
1964) and Generation X (born 1965 to 1982), when
the accent fell off a cliff.

“We had been listening to hundreds of hours of
speech recorded in Georgia and we noticed that
older speakers often had a thick Southern drawl,
while current college students didn’t,” Renwick
said. “We started asking, which generation of
Georgians sounds the most Southern of all? We
surmised that it was baby boomers, born around
the mid-20th century. We were surprised to see
how rapidly the Southern accent drops away
starting with Gen X.”
....

“The demographics of the South have changed a
lot with people moving into the area, especially
post World War II,” said co-author Jon Forrest,
UGA assistant professor in the department of
linguistics. Forrest noted that what the
researchers see in Georgia is part of a shift
noted by others across the entire South, and
furthermore, other areas of the U.S. now have
similar vowel patterns.
....

https://www.cambridge.org/core/journals/language-variation-and-change/article/boomer-peak-or-gen-x-cliff-from-svs-to-lbms-in-georgia-english/6AEA44E9263DFAE376F3BB20E087E5F9
Boomer Peak or Gen X Cliff? From SVS to LBMS
in Georgia English

Abstract
The late twentieth century in the United States
marks the decline of regional vowel systems
like the Northern Cities Shift and the Southern
Vowel Shift, replaced by supralocal systems
like the Low-Back-Merger Shift. We chart such
change in acoustic data from seven generations
of White speakers (n = 135) in the Southeastern
state of Georgia. We analyze front vowels
affected by both the SVS and LBMS (DRESS, TRAP),
plus PRICE and FACE, known respectively to
monophthongize and centralize in the SVS, and
LBMS-implicated LOT/THOUGHT. The SVS is most
advanced among Georgians born in the
mid-twentieth century, particularly in
FACE-centralization. In Generation X, retraction
of front lax vowels begins, leading toward the
LBMS. These results, which hold across genders
and education levels, support findings that
regional vowel systems declined precipitously
following a Gen X “cliff,” raising questions
about how such language changes are rooted in
demographic transformations of that time period.