A History of Short Words

From the New York Times Crossword Puzzle

ESTO

Sun, 3 Apr '22
This: Sp.
Mon, 21 Mar '22
This, in Spanish
Sun, 20 Feb '22
"Salus populi suprema lex ___" (motto of Missouri)
Fri, 21 May '21
"Qué es ___?" ("What's this?": Sp.)