Quotation marks are not appearing adequately

Question

In certain documents of mine, the quotation marks are displayed incorrectly. For instance, while writing down `word', as usual, the word is formatted within two reverse backticks.

Some of my other files do not display the same problem. I generally recycle my headers. I've tried in a process of elimination to locate which part of the header is responsible for this state of affairs but so far, have not been successful. My headers are becoming more and more messy and cluttered, many times with packages and styles that are not even called by the document.

I hereby present one header of a document that is rendering this problem:

\documentclass[12pt]{article}
\usepackage{geometry}             
\geometry{letterpaper}
\usepackage{graphicx}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{epstopdf}
\usepackage{txfonts}

\usepackage{enumerate}
\usepackage[autostyle]{csquotes}

\usepackage{tikz}
\usetikzlibrary{shapes,arrows,positioning}
\tikzstyle{int}=[draw, minimum size=2em]
\tikzstyle{init} = [pin edge={to-,thin,black}]

\usepackage{mathpazo}
\usepackage{lettrine}

\DeclareGraphicsRule{.tif}{png}{.png}{`convert #1 `dirname #1`/`basename #1 .tif`.png}
\DeclareMathSymbol{\boxright}{\mathrel}{symbolsC}{128}
\DeclareMathOperator*{\Max}{Max}

\usepackage[round]{natbib}

\def\Vox{$^{\fbox {\/}}$}
\def\dalem{\mbox{\Vox}}
\def\prom{
\newtheorem{prop}{Proposition}[section]
\newtheorem{cor}[prop]{Corollary}
\newtheorem{lem}[prop]{Lemma}
\newtheorem{exa}[prop]{Example}
\newtheorem{sch}[prop]{Scholium}
\newtheorem{rem}[prop]{Remark}
\newtheorem{axi}[prop]{Axiom System}
\newtheorem{con}[prop]{Conjecture}
\newtheorem{theor}[prop]{Theorem}
\newtheorem{cla}[prop]{Claim}
\newtheorem{hypo}[prop]{Hypothesis}
\newtheorem{tef}[prop]{Definition}}

\pagestyle {myheadings}

\prom

\tikzset
{
box/.style={rectangle,rounded corners,draw=black, very thick, text width=7.5em, minimum height=2em,text centered},
}

\title{XXX}
\author{XXX}
\date{\today}

\begin{document}

Sorry for the inconvenience. Thank you very much in advance.

Answer 1

Removing the mathpazo package and including babel with USenglish, I've got the result desired with no errors or warnings.

\documentclass[12pt]{article}
\usepackage[USenglish]{babel}
\usepackage{geometry}             
\geometry{letterpaper}
\usepackage{graphicx}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{epstopdf}
\usepackage{txfonts}

\usepackage{enumerate}
\usepackage[autostyle]{csquotes}

\usepackage{tikz}
\usetikzlibrary{shapes,arrows,positioning}
\tikzstyle{int}=[draw, minimum size=2em]
\tikzstyle{init} = [pin edge={to-,thin,black}]

%\usepackage{mathpazo}
\usepackage{lettrine}

\DeclareGraphicsRule{.tif}{png}{.png}{`convert #1 `dirname #1`/`basename #1 .tif`.png}
\DeclareMathSymbol{\boxright}{\mathrel}{symbolsC}{128}
\DeclareMathOperator*{\Max}{Max}

\usepackage[round]{natbib}

\def\Vox{$^{\fbox {\/}}$}
\def\dalem{\mbox{\Vox}}
\def\prom{
\newtheorem{prop}{Proposition}[section]
\newtheorem{cor}[prop]{Corollary}
\newtheorem{lem}[prop]{Lemma}
\newtheorem{exa}[prop]{Example}
\newtheorem{sch}[prop]{Scholium}
\newtheorem{rem}[prop]{Remark}
\newtheorem{axi}[prop]{Axiom System}
\newtheorem{con}[prop]{Conjecture}
\newtheorem{theor}[prop]{Theorem}
\newtheorem{cla}[prop]{Claim}
\newtheorem{hypo}[prop]{Hypothesis}
\newtheorem{tef}[prop]{Definition}}

\pagestyle {myheadings}

\prom

\tikzset
{
box/.style={rectangle,rounded corners,draw=black, very thick, text width=7.5em, minimum height=2em,text centered},
}

\title{XXX}
\author{XXX}
\date{\today}

\begin{document}

    Do not be alarmed. This is a `kindness'.
\end{document}