\section{ \textit{}} 中缺少 IPA 字符

Question

当特定 IPA 字符（例如 ʁ、ɢ、ʔ、ʃ）在上下文中以斜体显示时，章节标题不会显示这些字符\section{\textit{}}。我使用 Keyman 作为我的 Unicode IPA 键盘布局，它可以很好地在段落、示例等中输入语言字符。但标题会出现奇怪的结果。然而，令人惊讶的是，标题在目录和图表列表中打印正确，包括那些未读的 IPA 符号。我读过有关类似问题的其他问题，但没有找到适合我的问题的选项。如您所见，我使用\usepackage{fontspec}和\usepackage{libertine}；我想知道最后一个包是否有问题。MWE 如下：

\documentclass[12pt, one side]{book}
\usepackage {setspace}
\onehalfspacing
\pagestyle{plain}
\usepackage{indentfirst}
\setlength{\parindent}{0.5cm}
\usepackage{fontspec}% Enable KEYMAN functionality
\usepackage{libertine}
begin{document}
%\hypertarget{TitlePage}{}
\maketitle
%\bookmark[dest=TitlePage]{Title Page}
\pagenumbering{roman}
\pdfbookmark[0]{\contentsname}{toc}
 \tableofcontents
 \newpage
 \printglosses
 \newpage
 \listoftables
 \clearpage
 \listoffigures
 \listoftodos
 \clearpage
\pagenumbering{arabic}
\chapter{Valence Alternations}
\section{Reciprocality and beyond: previous work and goals}
This section describes the range of uses of the suffix \textit{-taʔ}. A previous work on the Mocoví spoken in Southern Chaco  analyzed \textit{-taʔ} as a \textit{reciprocal} verb marker \citep[see][45]{Gualdieri1998}.  This work provides further data on the uses of \textit{-taʔ} focusing on its syntactic and semantic properties.   

\section{The functionality of \textit{-taʔ}}
\subsection{Transitive predicates}
The suffix \textit{-taʔ} can in fact be used to express reciprocal constructions and occurs as the rightmost suffix of the verb morphological structure, as shown in (\ref{reciprocal marking}).    
%%%Rememeber that I'm using the {tipa} package. I'm not sure if this is the most practical package. It gives me the font but I think there is another option for the same output,  look for it. 
\end{document}

Answer 1

在我的测试中，使用 libertinus 而不是 libertine 对我认为是您的那个问题没有影响。但 \usepackage[sb]{libertine} 可以工作。显然粗体斜体变体中有一个错误。libertinus 开发人员应该能够为他们的字体修复它。