Quote (ditto marks) to avoid repeating a text

Question

In a document I am writing I have a list close to this one:

\begin{itemize}
    \item \emph{c} before \emph{e} or \emph{i} is pronounced as in \emph{church}
    \item \emph{g} before \emph{e} or \emph{i} is pronounced as in \emph{gin}
\end{itemize}

Of course, there is a large portion of repeated text. Is it possible to replace it with a single character ” centered ans taking the right width?

The final result should look like:

c before e or i is pronounced as in church
g             ”               as in gin

Answer 1

You can measure the width of the text and use it for a box of the same width that only contains, say, quotes.

\documentclass{article}
\begin{document}
\setbox0\hbox{before \emph{e} or \emph{i} is pronounced}
\begin{itemize}
    \item \emph{c} before \emph{e} or \emph{i} is pronounced as in \emph{church}
    \item \emph{g} \makebox[\the\wd0][c]{"}  as in \emph{gin}
\end{itemize}
\end{document}

And you can use macros to abbreviate it.

\documentclass{article}
\setbox0\hbox{before \emph{e} or \emph{i} is pronounced}
\newcommand{\pft}{\makebox[\the\wd0][c]{"}\ }
\begin{document}
\begin{itemize}
    \item \emph{c} before \emph{e} or \emph{i} is pronounced as in \emph{church}
    \item \emph{g} \pft  as in \emph{gin}
\end{itemize}
\end{document}

Answer 2

You can have something like this with package eqparbox (two variants):

\documentclass{article}
\usepackage{eqparbox} 

\begin{document}

\begin{itemize}
\item \emph{c} \eqmakebox[NR]{before \emph{e} or \emph{i} is pronounced as in} \emph{church}
\item \emph{g} \eqmakebox[NR]{ — } \emph{gin}
\item \emph{g} \eqmakebox[NR][s]{ — — — } \emph{gin}
\end{itemize}

\end{document} 

Answer 3

Your suggestions are // or <<, each two characters. Why not three characters?

\newcommand{\QW}{before \emph{e} or \emph{i} is pronounced as in }
% ...
\item \emph{c} \QW \emph{church}

Choose whatever works for you as the two letter macro name.

While I was writing the above answer the questioner "clarified" the question. It turned out that the clarification nullified this answer to the original question.

EDIT

Here's another (long-winded) answer to your revised question. Use a tabular.

% repeatprob.tex SE 513244  avoid repeating text

\documentclass{article}

\begin{document}
\newcommand*{\MB}{$\bullet$}
\newcommand*{\RP}{------ '' ------}
% for even less text
\newcommand*{\Entry}[2]{\MB & \emph{#1} & \RP \emph{#2} \\}

\setlength{\tabcolsep}{1pt}
\begin{tabular}{cccl}
$\bullet$ & \emph{c} & before \emph{e} or \emph{i} is pronounced as in & \emph{church} \\
\MB & \emph{g} & '' & \emph{gin} \\
\MB & \emph{g} & \RP & \emph{gin} \\
\Entry{g}{gin}
\end{tabular}

\end{document}

GOM (Grumpy Old Man)