Greek and English in lstlisting

I’m trying to create an lstlisting that contains both english and greek letters.

I have set this style.

lstset{
      basicstyle=normalsizeselectlanguage{english}ttfamily,  % COURIER NEW?
    frame=tb, % draw a frame at the top and bottom of the code block
    tabsize=4, % tab space width
    showstringspaces=false, % don't mark spaces in strings
    numbers=left, % display line numbers on the left
    commentstyle=color{black}, % comment color
    keywordstyle=color{black}, % keyword color
    stringstyle=color{black} % string color
}

and I want to include this code inside the lstlisting. As you can see there is greek text: ‘Σύνθετη Αναζήτηση’. However when i run the pdfLatex compiler, it is rendered in latin character.

begin{lstlisting}
<?php

function custom_toolbar_link($wp_admin_bar) {
    $args = array(
        'id' => 'advanced_search',
        'title' => 'Σύνθετη Αναζήτηση',
        'href' => 'admin.php?page=advanced-search',

        'meta' => array(
            'class' => 'advanced_search',
            'title' => 'advanced search'
        )
    );
    $wp_admin_bar->add_node($args);
}
add_action('admin_bar_menu', 'custom_toolbar_link', 10);
end{lstlisting}

Can you help me?

*** A full minimal example of the text:

documentclass[11pt,a4paper,fleqn]{article}
usepackage{listings}
usepackage{dirtree}
usepackage{indentfirst}
usepackage[greek,english]{babel}
usepackage[iso-8859-7]{inputenc}
usepackage{chicago}
usepackage[section]{placeins}

lstset{
      basicstyle=normalsizeselectlanguage{english}ttfamily,  % COURIER NEW?
    frame=tb, % draw a frame at the top and bottom of the code block
    tabsize=4, % tab space width
    showstringspaces=false, % don't mark spaces in strings
    numbers=left, % display line numbers on the left
    commentstyle=color{black}, % comment color
    keywordstyle=color{black}, % keyword color
    stringstyle=color{black} % string color
}

% This concludes the preamble
begin{document}

begin{lstlisting}[label=some-code,caption=Some Code]
<?php
function custom_toolbar_link($wp_admin_bar) {
    $args = array(
        'id' => 'advanced_search',
        'title' => 'Σύνθετη Αναζήτηση',
        'href' => 'admin.php?page=advanced-search',
        'meta' => array(
            'class' => 'advanced_search',
            'title' => 'advanced search'
        )
    );
    $wp_admin_bar->add_node($args);
}
add_action('admin_bar_menu', 'custom_toolbar_link', 10);
end{lstlisting}

end{document}

begin{lstlisting}[label=some-code,caption=Some Code,escapeinside=;;]
<?php
function custom_toolbar_link($wp_admin_bar) {
$args = array(
'id' => 'advanced_search',
'title' => ';selectlanguage{greek}Σύνθετη Αναζήτησηselectlanguage{english};',
'href' => 'admin.php?page=advanced-search',
'meta' => array(
'class' => 'advanced_search',
'title' => 'advanced search'
)
);
$wp_admin_bar->add_node($args);
}
add_action('admin_bar_menu', 'custom_toolbar_link', 10);
end{lstlisting}