Index: src/wp-admin/includes/meta-boxes.php
===================================================================
--- src/wp-admin/includes/meta-boxes.php	(revision 41217)
+++ src/wp-admin/includes/meta-boxes.php	(working copy)
@@ -446,7 +446,7 @@
 	<div class="ajaxtag hide-if-no-js">
 		<label class="screen-reader-text" for="new-tag-<?php echo $tax_name; ?>"><?php echo $taxonomy->labels->add_new_item; ?></label>
 		<p><input data-wp-taxonomy="<?php echo $tax_name; ?>" type="text" id="new-tag-<?php echo $tax_name; ?>" name="newtag[<?php echo $tax_name; ?>]" class="newtag form-input-tip" size="16" autocomplete="off" aria-describedby="new-tag-<?php echo $tax_name; ?>-desc" value="" />
-		<input type="button" class="button tagadd" value="<?php esc_attr_e('Add'); ?>" /></p>
+		<input type="button" class="button tagadd" value="<?php esc_attr_e('&#9166;'); ?>" /></p>
 	</div>
 	<p class="howto" id="new-tag-<?php echo $tax_name; ?>-desc"><?php echo $taxonomy->labels->separate_items_with_commas; ?></p>
 	<?php elseif ( empty( $terms_to_edit ) ): ?>
Index: src/wp-includes/class-wp-customize-control.php
===================================================================
--- src/wp-includes/class-wp-customize-control.php	(revision 41217)
+++ src/wp-includes/class-wp-customize-control.php	(working copy)
@@ -605,7 +605,7 @@
 					<div class="new-content-item">
 						<label for="create-input-<?php echo $this->id; ?>"><span class="screen-reader-text"><?php _e( 'New page title' ); ?></span></label>
 						<input type="text" id="create-input-<?php echo $this->id; ?>" class="create-item-input" placeholder="<?php esc_attr_e( 'New page title&hellip;' ); ?>">
-						<button type="button" class="button add-content"><?php _e( 'Add' ); ?></button>
+						<button type="button" class="button add-content"><?php _e( '&#9166;' ); ?></button>
 					</div>
 				<?php endif;
 				break;
Index: src/wp-includes/class-wp-customize-nav-menus.php
===================================================================
--- src/wp-includes/class-wp-customize-nav-menus.php	(revision 41217)
+++ src/wp-includes/class-wp-customize-nav-menus.php	(working copy)
@@ -1007,7 +1007,9 @@
 					<?php if ( current_user_can( $post_type_obj->cap->create_posts ) && current_user_can( $post_type_obj->cap->publish_posts ) ) : ?>
 						<div class="new-content-item">
 							<input type="text" class="create-item-input" placeholder="<?php echo esc_attr( $post_type_obj->labels->add_new_item ); ?>">
-							<button type="button" class="button add-content"><?php _e( 'Add' ); ?></button>
+							<button type="button" class="button add-content">
+								<span class="screen-reader-text"><?php _e( 'Add' ); ?></span>
+							</button>
 						</div>
 					<?php endif; ?>
 				<?php endif; ?>