Polyglossia language from script?

Question

When the different languages I use in a document have different scripts, can I implicitly set language from the script?

Here is a MWE in English and Russian where the Russian works fine when marked up as it should. My wish is to be able to say that cyrillic script means Russian so that the last paragraph also is done right.

% -*- TeX-engine: xetex; -*-
\documentclass[draft]{article}
\usepackage{polyglossia}
\setmainlanguage{english}
\setotherlanguage{russian}
\setmainfont{Linux Libertine}

\begin{document}
\hsize 4.6cm

This is the main text is English.

\begin{russian}
Русский язык очень красивый.
\end{russian}

Русский язык очень красивый.
\end{document}

Answer 1

You can use ucharclasses, but my recommendation is to mark up your document with language changes.

\documentclass{article}
\usepackage{polyglossia}
\setmainlanguage{english}
\setotherlanguage{russian}
\setmainfont{Linux Libertine O}

\usepackage[Latin,Cyrillics]{ucharclasses}

\setTransitionsForCyrillics
  {\begingroup\hyphenrules{russian}}
  {\endgroup}

\begin{document}
\hsize 4.7cm

This is the supercalifragilisticexpialidocious text

Русский язык очень красивый.

This is the supercalifragilisticexpialidocious text

\end{document}