Using Courier New font when main language uses cyrillic script [duplicate]

Question

If I set language that uses cyrillic script as the default one, I can't use font Courier New.

\documentclass{article}
\usepackage{fontspec}
\usepackage{polyglossia}
\setmainlanguage{russian}
\setmonofont{Courier New}
\newfontfamily\cyrillicfont{Courier New}
\begin{document}
\texttt{русский язык}
\end{document}

The compiler is complaining:
! Package polyglossia Error: The current roman font does not contain the Cyrillic script! (polyglossia) Please define \cyrillicfont with \newfontfamily.

But, as you can see, Courier New is defined with \newfontfamily\cyrillicfont{Courier New}.

I compile with XeLaTeX.

Edit: polyglossia package is required.

Answer 1

polyglossia is strict about scripts in fonts. So if a font doesn't have Cyrillic script defined, it won't allow you to use it. Particularly for Courier New:

% otfinfo -s Courier_New.ttf
arab            Arabic
arab.URD        Arabic/Urdu
hebr            Hebrew
latn            Latin
latn.LTH        Latin/Lithuanian
latn.ROM        Latin/Romanian

babel on the other hand doesn't bother about scripts, it just requires Cyrillic characters to be in place. The following code works fine:

\documentclass{article}
\usepackage{fontspec}
\usepackage[russian]{babel}
\setmonofont{Courier New}
\begin{document}
\texttt{русский язык}
\end{document}

Answer 2

Use \newfontfamily\cyrillicfonttt{Courier New}.

\documentclass{article}
\usepackage{fontspec}
\usepackage{polyglossia}
\setmainlanguage{russian}
\setmainfont{Arial}
\newfontfamily\cyrillicfont{Arial}
\setmonofont{Courier New}
\newfontfamily\cyrillicfonttt{Courier New}
\begin{document}
\texttt{русский язык}
\end{document}