biblatex: mismatched quotation marks (italic/roman)

Question

The Chicago Manual of Style says punctuation and quotation marks should match the surrounding rather than the enclosed font (i.e. roman or italic), unless they form part of a title, in which case they take on the font of the title (§§ 6.2, 6.5; cf. 14.102).

I take this to mean that in Book Title "Including a Second Title," the opening and closing quotation marks should both be in italic. What to do with the comma is another issue.

Now, if I do exactly what the biblatex-chicago example bibliography does in this sort of situation -- i.e. format my bibliography in accordance with this answer --, I end up with an italic opening quotation mark and a roman closing quotation mark. It looks fine in the biblatex-chicago example PDF, but I suspect that's because the font used makes little or no difference between italic and roman quotation marks. When I recompile it with Computer Modern, I find it hard to tell a difference, again because it seems not to have very distinct italic quotes. But if I substitute the Cardo font, say, the closing quote is clearly roman where I imagine it should be italic like its peer.

XeLaTeX MWE:

\documentclass{book}
\usepackage{fontspec}
\usepackage{polyglossia}
\usepackage[style=american]{csquotes}
\usepackage[notes]{biblatex-chicago}

\setmainfont[Ligatures=TeX]{Cardo}
\setmainlanguage{english}
\begin{filecontents}{book.bib}
@book{key1,
   author = {David Byrne},
   title = {This Book Title Ends in \mkbibquote{Quotation Marks}},
   location = {Oxford},
   publisher = {Oxford University Press},
   year = {2012}
}
\end{filecontents}
\addbibresource{book.bib}

\begin{document}

Here I cite a book whose title ends in a closing quotation mark\autocite[55]{key1}.
\printbibliography

\end{document}

_{(source: langeslag.org)}

I've tried adding \setpunctfont\emph, but no difference. Any ideas?

Answer 1

Your code is not particularly minimal, since most of the packages in your preamble have nothing to do with the problem you've identified.

When I put works with quotation marks in my .bib file, I've always just used the standard LaTeX method of typing `` and ''. That has always worked for me, and it works in this case, too. Why are you using \mkbibquote exactly?

\documentclass{book}
\usepackage{fontspec}
    \setmainfont{Cardo}
\usepackage[style=american]{csquotes}
\usepackage{biblatex-chicago}
\begin{filecontents}{book.bib}
@book{key1,
   author = {David Byrne},
   title = {This Book Title Ends in ``Quotation Marks''},
   location = {Oxford},
   publisher = {Oxford University Press},
   year = {2012}
}
\end{filecontents}
\addbibresource{book.bib}

\begin{document}
Here I cite a book whose title ends in a closing quotation mark\autocite[55]{key1}.
\printbibliography
\end{document}