function author_comment_count(){
 
	    $oneText = '1';
	    $moreText = '%';
 
	    global $wpdb;
 
	    $result = $wpdb->get_var('
	        SELECT
	            COUNT(comment_ID)
	        FROM
	            '.$wpdb->comments.'
	        WHERE
	            comment_author_email = "'.get_comment_author_email().'"'
	    );
 
	    if($result == 1):
 
	        echo str_replace('%', $result, $oneText);
 
	    elseif($result > 1):
 
	        echo str_replace('%', $result, $moreText);
 
	    endif;
 
	}
 
 
 
To display an author’s total number of comments, use the function like this inside of your comments loop :
 
	author_comment_count();