I'm experiencing problems with Linguex. For some reason, weird symbols are appearing in some of my examples. The relevant part of the code is given below and the output is in the screenshot. Thank you in advance for your help!
\documentclass[11pt;a4paper]{article}
\usepackage{linguex}
\usepackage{apacite}
\usepackage{latexsym} %symbols
\usepackage{comment}
\usepackage{stmaryrd} %symbols
\usepackage{amssymb} %symbols
\usepackage{qtree}
\usepackage{amsmath} %symbols
\usepackage{url}
\usepackage[normalem]{ulem}%for \sout
\usepackage{float}%to keep tables in their place
\usepackage{color}%for changing the text colour
\usepackage{tikz} %for circles around symbols and other fancy stuff
\usepackage[T1]{fontenc}%for Scandinavian letters
\newcommand*\circled[1]{\tikz[baseline=(char.base)]{
\node[shape=circle,draw,inner sep=1pt] (char) {#1};}}%circle around symbols
\newcommand{\sem[1]}{$\llbracket$#1$\rrbracket$}%sembrackets
\usepackage{tree-dvips}%for arrows in trees
\begin{document}
\ex. $\neg$ [$\Box$ [$\exists x$ [$x$ is a merchant and Petronella marries $x$]]]\label{51220173}
\ex. \label{51220175}\a. Surface scope: what Petronella wants to do is to marry no merchant\\
$\Box > \neg \exists$
\b. Inverse scope: there is no specific merchant Petronella wants to marry\\
$\neg\exists > \Box$\label{51220175b}
\c. Split scope: Petronella does not want to marry a merchant\\
$\neg > \Box > \exists$
\end{document}
