Foreign language quotation marks with babel and csquotes on pdfLaTeX

Question

I haven't been able to switch the quotation marks from Spanish to English in the document resulting from the MWE below. What, if anything, am I doing wrong or missing? And, yes, I've also tried by reversing the loading order of the polyglossia/babel and csquotes packages.

\documentclass{memoir}

\usepackage{xifthen, ifpdf, ifxetex}
\ifxetex
\usepackage{polyglossia}
  \setdefaultlanguage{spanish}
  \setotherlanguages{greek, english}
\else
\usepackage[greek, english, spanish, es-lcroman]{babel}
\fi

\usepackage{csquotes}

\begin{document}
\enquote{Quoted text} \par
\foreignquote{english}{English quotation marks}
\end{document} 

Answer 1

You need to pass the autostyle=true option to csquotes:

\documentclass{memoir}

\usepackage{xifthen, ifpdf, ifxetex}
\ifxetex
\usepackage{polyglossia}
  \setdefaultlanguage{spanish}
  \setotherlanguages{greek, english}
\else
\usepackage[greek, english, spanish, es-lcroman]{babel}
\fi

\usepackage[autostyle=true]{csquotes}

\begin{document}
\enquote{Quoted text} \par
\foreignquote{english}{English quotation marks}
\end{document} 

By default autostyle is tryonce, so the quotation style is fixed after the first use. Older csquotes had an option babel, but this has been replaced by autostyle, which will work with both babel and polyglossia.