The 2019–20 coronavirus pandemic resulted in many requirements to wear face masks. The masks often made it harder to communicate. 
 
“After six months of listening to people talk with masks on I finally understand what Charlie Brown’s teacher was saying 🤣” was posted on Facebook by Bee Good on September 6, 2020. “Charlie Brown” is a lead character in the Peanuts comic strips and movies. The teacher’s voice was given the “wah-wah” sound of a trombone.
 
   
Wikipedia: 2019-20 coronavirus outbreak
The 2019–20 coronavirus pandemic is an ongoing global pandemic of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The outbreak was first identified in Wuhan, Hubei, China, in December 2019, and was recognised as a pandemic by the World Health Organization (WHO) on 11 March 2020.
     
Mashable
The story of Wah Wah and other ‘Peanuts’ specials secrets
BY LANCE ULANOFF
OCT 26, 2015
(...)
Now 82 and living just outside San Francisco, Mendelson told Mashable, “We chose not to show the adult. So I asked our music director, Vince Guaraldi, ‘Would there be some instrument we could use as a sound to emulate what an adult might sound like to a kid?’”
 
Guaraldi, who first collaborated with Schulz and Mendelson on a 1963 documentary about the comic strip legend, didn’t hesitate. He brought in a trombone player.
 
YouTube
Charlie Brown’s teacher - Sound Effect
Jul 7, 2016
Partexedd
     
Facebook
Bee Good
September 6, 2020 at 6:02 PM ·
After six months of listening to people talk with masks on I finally understand what Charlie Brown’s teacher was saying 🤣
 
Twitter
jlynn
@lynnxoox
After six months of listening to people talk with masks on I finally understand what Charlie Brown’s teacher was saying.
8:17 AM · Sep 10, 2020·Twitter for iPhone
 
Facebook
Mindi Honey
September 10, 2020 at 9:35 PM ·
After six months of listening to people talk with masks on I finally understand what Charlie Brown’s teacher was saying 🤣
 
Facebook
Jason Howell
September 10, 2020 at 11:02 PM ·
After six months of listening to people talk with masks on I finally understand what Charlie Brown’s teacher was saying 🤣
 
Twitter
Dan
@dannyoneofmany
#FridayThoughts
After six months of listening to people talk with masks on I finally understand what Charlie Brown’s teacher was saying
#HappyFriday
5:56 AM · Sep 11, 2020·Twitter for Android
 
Facebook
im not right in the head.com
September 11, 2020 ·
Shared by Mark Hyde
After six months of listening to people talk with masks on I finally understand what Charlie Brown’s teacher was saying 🤣