In a book my daughter is reading, I found the following usage of the unfamiliar symbols:
But those words dont help. So I reach over, wipe away his tear with the side of my thumb, and say the only words I know will calm him: “‘”Frog, you are looking quite green.”‘”
David sniffles. “‘”But I always look green,” said Frog. “I am a frog.”‘”
I pause, pretending I don’t remember what comes next, though I can do the entire book word for word, by heart.
“‘”Today you look very green, even for a frog,” said Toad.'” David looks at me.
There are three nested sets of quotation marks here. The speaker (David’s mother, presumably) is quoting the book Frog and Toad by Arnold Lobel. In this book, either Toad or Frog is speaking. You get the outermost set of quotation marks (“) because David’s mother is speaking. The next set of quotation marks (‘) arises because David’s mother is quoting from the book Frog and Toad. Finally, the inner set of quotation marks (“) comes because, in the book, Toad (or Frog) himself is speaking. So:
“ ’ ”Today you look very green, even for a frog,” said Toad.’ ”
This starts with David quoting from the book, and Toad is speaking at the beginning of the quote, so you get three quotation marks. The innermost one ends halfway through, when Toad stops speaking. At the end of the sentence, David stops speaking and stops quoting the book at the same time, so you get two sets.
I have never seen three nested quotation marks before. They are used correctly, but are nevertheless very confusing.