Quotes don't work with polyglossia?

Question

I have an older file using `` and '' which would then be formatted as proper quotes. I was now wanting to use polyglossia for that file and find that while these quotes still work in the footnotes, they don't do so anymore in the running text:

\documentclass{article}
\usepackage{polyglossia}
\setdefaultlanguage{english}
\setotherlanguage{sanskrit}
\setotherlanguage{german}
\newfontfamily\sanskritfont{Latin Modern Roman}
\newfontfamily\englishfont{Latin Modern Roman}
\begin{document}
``Test''\footnote{``Test''}
\end{document}

Was I just using some ancient crutch one should not be using anymore nowadays?

Answer 1

If you define an \englishfont you need to activate the ligatures for it:

\documentclass{article}
\usepackage{polyglossia}
\setdefaultlanguage{english}
\setotherlanguage{sanskrit}
\setotherlanguage{german}
\newfontfamily\sanskritfont{Latin Modern Roman}
\newfontfamily\englishfont{Latin Modern Roman}[Ligatures=TeX]
\begin{document}
``Test''\footnote{``Test''}
\end{document}