How can I get the English words in this mostly-Greek document not to render in Greek characters?

Question

I'm trying to set a book in polytonic Greek with English sprinkled here and there throughout, but for some reason, when I try to switch to English, the characters stay Greek. Here's a MWE:

\documentclass{book}
\usepackage[LGR]{fontenc}
\usepackage[greek,english]{babel}
\languageattribute{greek}{polytonic}
\usepackage{dialogue}

\begin{document}
\selectlanguage{greek}

τὸ πλοῖον ἐστιν ἐν Βυζαντίῳ. 

\begin{dialogue}
\speak{ΖΗΝΟΘΕΜΙΣ} \selectlanguage{english}\direct{pointing to the land} \selectlanguage{greek}δεῦρο ἐλθέ, ὦ Δικαιόπολι, καὶ βλέπε. ἐγὼ γὰρ τὴν ἀκρόπολιν ὁρῶ. ἆρα καὶ σὺ τὴν ἀκρόπολιν ὁρᾷς;
\end{dialogue}

\end{document}

The above code, which I thought would produce, along with the Greek, the English phrase in brackets "pointing to the land," produces this instead:

Any ideas about what I'm doing wrong?

Answer 1

You no longer need to load the LGR encoding (it used to be necessary up to a few years ago). Also you want to use \foreignlanguage{english}{...} rather than \selectlanguage back and forth.

Since Greek is the main language, specify it last.

Better yet, use a new command.

\documentclass{book}
\usepackage[english,greek]{babel}
\languageattribute{greek}{polytonic}

\usepackage{dialogue}

\newcommand{\engdirect}[1]{\direct{\foreignlanguage{english}{#1}}}

\begin{document}

τὸ πλοῖον ἐστιν ἐν Βυζαντίῳ. 

\begin{dialogue}
\speak{ΖΗΝΟΘΕΜΙΣ} \engdirect{pointing to the land} δεῦρο ἐλθέ, ὦ Δικαιόπολι, 
  καὶ βλέπε. ἐγὼ γὰρ τὴν ἀκρόπολιν ὁρῶ. ἆρα καὶ σὺ τὴν ἀκρόπολιν ὁρᾷς;
\end{dialogue}

\end{document}