Change posted by .. on.. in twenty eleven

Try use the google translate plugin

Thanks, but will this translate on the admin page or the entire homepage?

Took me hours to figure that out. But I made it like this (not the best way, even stupid, I guess, but it works)
Make a new functions.php file in your childtheme and copy this text:

<?php
if ( ! function_exists( 'twentyeleven_posted_on' ) ) :
/**
 * Prints HTML with meta information for the current post-date/time and author.
 * Create your own twentyeleven_posted_on to override in a child theme
 *
 * @since Twenty Eleven 1.0
 */
function twentyeleven_posted_on() {
	printf( __( '<span class="sep">Geplaatst op </span><a href="%1$s" title="%2$s" rel="bookmark"><time class="entry-date" datetime="%3$s" pubdate>%4$s</time></a><span class="by-author"> <span class="sep"> by </span> <span class="author vcard"><a class="url fn n" href="%5$s" title="%6$s" rel="author">%7$s</a></span></span>', 'twentyeleven' ),
		esc_url( get_permalink() ),
		esc_attr( get_the_time() ),
		esc_attr( get_the_date( 'c' ) ),
		esc_html( get_the_date() ),
		esc_url( get_author_posts_url( get_the_author_meta( 'ID' ) ) ),
		esc_attr( sprintf( __( 'View all posts by %s', 'twentyeleven' ), get_the_author() ) ),
		get_the_author()
	);
}
endif;
?>

Where it says ‘geplaatst op’ change that to your Publisert.
Have fun.