How Limit show Child Pages titles and characters?

Hello guys,

I have a function that shows the titles of childpages of certain pages with shortcode.

The problem is I have 18 childpages and he is showing me all.

I would like to stay:
childpag…
childpag…
childpag…
childpag…
childpag…

I could limit the amount of titles and limit the number of characters.

//Add a shortcode for listing child pages of a parent page
function list_pages_shortcode( $atts ) {
    // Basic shortcode markup
    extract( shortcode_atts( array(
        'post_parent' => false,
        'title' => '',
    ), $atts ) );

    //If the post parent attribute isn't specified, use the current post's ID
    if ( ! $post_parent ) {
    global $post;
        if ( is_object( $post ) ) {
            $post_parent = $post->ID;
        } else {
            return false;
        }
    }

    //Build the arguments - we want the child of the post_parent
    $args = array(
        'depth'        => 3,
        'child_of'     => $post_parent,
        'title_li'     => $title,
        'echo'         => 0,
        'sort_column'  => 'menu_order, post_title'
        );

    // if there is no title lets barf up the wordpress pages instead
    if ( empty( $title ) ) {
        return "<ul>" . wp_list_pages( $args ) . "</ul>";
    } else {
        return wp_list_pages( $args );
    }
}
add_shortcode( 'list_subpages', 'list_pages_shortcode' );

Thank you!