mwe.tex

\documentclass[american]{article}
\usepackage[american]{babel}
\usepackage[autostyle]{csquotes}%
\usepackage[backend=biber, style=apa]{biblatex}
\DeclareLanguageMapping{american}{american-apa}
%\usepackage{fontspec}
%\setmainfont{Linux Libertine}
\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}

@article{a,
  author       = {Doe, John},
  year         = {2015},
  title        = "Why Is Apple Launching a New Version of the {{iPod}}?"
}
@article{b,
  author       = {Doe, John},
  year         = {2015},
  title        = "Why Is {{Apple}} Launching a New Version of the {{iPod}}?"
}
@article{c,
  author       = {Doe, John},
  year         = {2015},
  title        = "Why is {{Apple}} launching a new version of the {{iPod}}?"
}
\end{filecontents}
%
\addbibresource{\jobname.bib}
\begin{document}
\cite{a}
\cite{b}
\cite{c}
\printbibliography
\end{document}