\documentclass [a4paper, 10pt] {article}
\pagestyle{plain}
\usepackage{polyglossia}
\defaultfontfeatures{Mapping=tex-text}
\setmainfont{DejaVu Sans}
\newfontfamily\englishfont{DejaVu Sans}
\setdefaultlanguage{english}
\begin{document}
The quick brown fox jumps over the lazy dog.
\end {document}