Mason taught middle and high school in SC for 17 years.
She dinged the Trump letter particularly for repeatedly capitalizing "nation", "federal", "president" and "state", turning these common nouns into proper nouns. "If it had been written in high school, I'd give it a D", Mason said.
The New York Times, which first reported the letter, says that Mason is a Democrat and former high school English teacher who retired a year ago and wrote to the President asking him to visit each family of those who died in the school shooting in Parkland, Florida, that took 17 lives.
Mason has since retired, but the veteran teacher recently received a letter that she had to publicly call out for its "stylistically appalling" prose.
Trump previously held a "listening session" with Parkland community members and the victims' parents to discuss the prevention of school shootings and mass-casualty gun violence. But according to Mason, the letter received by her was full of grammatical mistakes.
You can see Mason made several corrections on the paper.
The teacher taught English at Hughes Middle School and Mauldin High School in Greenville for nearly two decades before retiring past year... There was a dangling modifier in the correspondence as well.More news: Morocco World Cup would be 'almost European'
There is no word if Mason's critique was received, as the White House has not commented on the issue.
Yvonne Mason said she does not abide poor writing. That depends: Is Trump writing at a middle school or high school level?
"It didn't address what I wrote", she said.
"You're important. You need to be a part of this, you need to pay attention to what's going on", she said. Instead of a direct response to her letter, however, Mason stated that what she received was the president's correspondence about general school safety.
Senator Lindsey Graham, Republican of SC, sent "beautiful" letters that struck a tone that "makes me more important than him", she said.
"Language is the currency of power", she said. "I understand the nature of form letters, but Graham's are written as if they're addressing your particular concern".