Index: wp-content/themes/twentyeleven/archive.php
===================================================================
--- wp-content/themes/twentyeleven/archive.php	(revision 18682)
+++ wp-content/themes/twentyeleven/archive.php	(working copy)
@@ -24,9 +24,9 @@
 						<?php if ( is_day() ) : ?>
 							<?php printf( __( 'Daily Archives: %s', 'twentyeleven' ), '<span>' . get_the_date() . '</span>' ); ?>
 						<?php elseif ( is_month() ) : ?>
-							<?php printf( __( 'Monthly Archives: %s', 'twentyeleven' ), '<span>' . get_the_date( 'F Y' ) . '</span>' ); ?>
+							<?php printf( __( 'Monthly Archives: %s', 'twentyeleven' ), '<span>' . get_the_date( _x( 'F Y', 'monthly archives date format', 'twentyeleven' ) ) . '</span>' ); ?>
 						<?php elseif ( is_year() ) : ?>
-							<?php printf( __( 'Yearly Archives: %s', 'twentyeleven' ), '<span>' . get_the_date( 'Y' ) . '</span>' ); ?>
+							<?php printf( __( 'Yearly Archives: %s', 'twentyeleven' ), '<span>' . get_the_date( _x( 'Y', 'yearly archives date format', 'twentyeleven' ) ) . '</span>' ); ?>
 						<?php else : ?>
 							<?php _e( 'Blog Archives', 'twentyeleven' ); ?>
 						<?php endif; ?>
Index: wp-content/themes/twentyten/archive.php
===================================================================
--- wp-content/themes/twentyten/archive.php	(revision 18682)
+++ wp-content/themes/twentyten/archive.php	(working copy)
@@ -32,9 +32,9 @@
 <?php if ( is_day() ) : ?>
 				<?php printf( __( 'Daily Archives: <span>%s</span>', 'twentyten' ), get_the_date() ); ?>
 <?php elseif ( is_month() ) : ?>
-				<?php printf( __( 'Monthly Archives: <span>%s</span>', 'twentyten' ), get_the_date( 'F Y' ) ); ?>
+				<?php printf( __( 'Monthly Archives: <span>%s</span>', 'twentyten' ), get_the_date( _x( 'F Y', 'monthly archives date format', 'twentyten' ) ) ); ?>
 <?php elseif ( is_year() ) : ?>
-				<?php printf( __( 'Yearly Archives: <span>%s</span>', 'twentyten' ), get_the_date( 'Y' ) ); ?>
+				<?php printf( __( 'Yearly Archives: <span>%s</span>', 'twentyten' ), get_the_date( _x( 'Y', 'yearly archives date format', 'twentyten' ) ) ); ?>
 <?php else : ?>
 				<?php _e( 'Blog Archives', 'twentyten' ); ?>
 <?php endif; ?>