diff --git a/php/class-wp-customize-post-setting.php b/php/class-wp-customize-post-setting.php
index 2638b57..d090bd9 100644
--- a/php/class-wp-customize-post-setting.php
+++ b/php/class-wp-customize-post-setting.php
@@ -345,7 +345,7 @@ public function sanitize( $post_data ) {
 
 		/** This filter is documented in wp-includes/post.php */
 		if ( 'trash' !== $post_data['post_status'] && apply_filters( 'wp_insert_post_empty_content', $maybe_empty, $post_data ) ) {
-			return $has_setting_validation ? new WP_Error( 'empty_content', __( 'Content, title, and excerpt are empty.', 'customize-posts' ), array( 'setting_property' => 'post_content' ) ) : null;
+			return $has_setting_validation ? new WP_Error( 'empty_content', __( 'Content, title, and excerpt are empty.', 'default' ), array( 'setting_property' => 'post_content' ) ) : null;
 		}
 
 		if ( empty( $post_data['post_status'] ) ) {
diff --git a/php/class-wp-customize-posts-panel.php b/php/class-wp-customize-posts-panel.php
index 1aad6ea..e98cd41 100644
--- a/php/class-wp-customize-posts-panel.php
+++ b/php/class-wp-customize-posts-panel.php
@@ -93,7 +93,7 @@ public function print_template() {
 			<# } else if ( data.text ) { #>
 				{{ data.text }}
 			<# } else { #>
-				<em><?php esc_html_e( '(No title)', 'customize-posts' ); ?></em>
+				<em><?php esc_html_e( '(no title)', 'default' ); ?></em>
 			<# } #>
 		</script>
 
diff --git a/php/class-wp-customize-posts.php b/php/class-wp-customize-posts.php
index dbea11d..a7fa36b 100644
--- a/php/class-wp-customize-posts.php
+++ b/php/class-wp-customize-posts.php
@@ -655,7 +655,8 @@ public function get_author_choices() {
 			foreach ( (array) $users as $user ) {
 				$choices[] = array(
 					'value' => (int) $user->ID,
-					'text'  => sprintf( _x( '%1$s (%2$s)', 'user dropdown', 'customize-posts' ), $user->display_name, $user->user_login ),
+					/* translators: 1: display name, 2: user login */
+					'text'  => sprintf( _x( '%1$s (%2$s)', 'user dropdown', 'default' ), $user->display_name, $user->user_login ),
 				);
 			}
 		}
@@ -680,7 +681,7 @@ public function get_date_month_choices() {
 			$month_text = $wp_locale->get_month_abbrev( $wp_locale->get_month( $i ) );
 
 			/* translators: 1: month number, 2: month abbreviation */
-			$months[ $i ]['text'] = sprintf( __( '%1$s-%2$s', 'customize-posts' ), $month_number, $month_text );
+			$months[ $i ]['text'] = sprintf( __( '%1$s-%2$s', 'default' ), $month_number, $month_text );
 			$months[ $i ]['value'] = $month_number;
 		}
 		return $months;
@@ -820,10 +821,10 @@ public function enqueue_scripts() {
 				'fieldSlugLabel' => __( 'Slug', 'customize-posts' ),
 				'fieldStatusLabel' => __( 'Status', 'customize-posts' ),
 				'fieldDateLabel' => __( 'Date', 'customize-posts' ),
-				'fieldContentLabel' => __( 'Content', 'customize-posts' ),
+				'fieldContentLabel' => __( 'Content', 'default' ),
 				'fieldExcerptLabel' => __( 'Excerpt', 'customize-posts' ),
 				'fieldDiscussionLabel' => __( 'Discussion', 'customize-posts' ),
-				'fieldAuthorLabel' => __( 'Author', 'customize-posts' ),
+				'fieldAuthorLabel' => __( 'Author', 'default' ),
 				'fieldParentLabel' => __( 'Parent', 'customize-posts' ),
 				'fieldOrderLabel' => __( 'Order', 'customize-posts' ),
 				'noTitle' => __( '(no title)', 'customize-posts' ),
@@ -1438,7 +1439,8 @@ public function ajax_insert_auto_draft_post() {
 		if ( is_wp_error( $r ) ) {
 			$error = $r;
 			$data = array(
-				'message' => sprintf( __( '%1$s could not be created: %2$s', 'customize-posts' ), $singular_name, $error->get_error_message() ),
+				/* translators: 1: singular post name, 2: error message */
+				'message' => sprintf( __( '%1$s could not be created: %2$s', 'default' ), $singular_name, $error->get_error_message() ),
 			);
 			wp_send_json_error( $data );
 		}