Change message for comments reply box theme 2011

simply want to change the message for visitors to the comment reply box

Do you want to change this message: “Leave a reply”?

Create a child theme for your changes.
You can download a pre-made Twenty Eleven child theme from here.

Put something like this in your child theme’s functions.php

add_filter( 'comment_form_defaults', 'change_form_defaults' );
function change_form_defaults( $defaults )
{
    // change the title "Leave a Reply"
    $defaults['title_reply'] = 'This is my own title';

    // change "Your email address will not be published. Required fields are marked *
    $defaults['comment_notes_before'] = 'Why u no comment';
    return $defaults;
}