In most fonts that I use it is the apostrophe/quotation marks.
However, when you type this letter the computer adjusts it. For example, when I type it in this standard font: " the computer recognizes whether it's a forward quotes or backwards quotes and CHANGES the character to reflect that. To undo that, you hit ctrl+z (command+z on mac).
So when you type in Coptic, it types Epsi then CHANGES the character because it doesn't recognize that Coptic is a language not a font.
Comments
However, when you type this letter the computer adjusts it. For example, when I type it in this standard font: " the computer recognizes whether it's a forward quotes or backwards quotes and CHANGES the character to reflect that. To undo that, you hit ctrl+z (command+z on mac).
So when you type in Coptic, it types Epsi then CHANGES the character because it doesn't recognize that Coptic is a language not a font.
So type the " or ' and hit Undo!