No.
"Could Of" is just poor English.
The correct form is Could Have.
When contracted, it is Could've ... which when spoken aloud is sometimes misconstrued as Could Of.
Look up a lot of slang terms and learn their meaningFigure out a good presentation - you could do a quiz with flash cards, or a board showing the slang terms - you could even dress up like someone from the past to show the slang of that era
In 1920s slang, "fun" could be described as a "gas" or "a barrel of monkeys."
"50 slang" could refer to slang from the 1950s (such as "cool cat" or "greaser") or slang that originated in the area code 50 in Minnesota. More context would be needed to provide a specific answer.
It could be short for picture.
It could be slang for prescription.
A palindrome for a slang term for a dumb person could be "dim mid."
The urban slang for "a little farther" could be "a bit more" or "a tad further."
You could say "I could eat a horse."
You could call them "rocks" or "sparklers."
Dollar could be: "Buck" or "green"
You could say fed up.
gag