diff --git a/src/wp-admin/includes/class-wp-upgrader.php b/src/wp-admin/includes/class-wp-upgrader.php
index 6995983d6f..d5e10c4c64 100644
--- a/src/wp-admin/includes/class-wp-upgrader.php
+++ b/src/wp-admin/includes/class-wp-upgrader.php
@@ -150,13 +150,13 @@ class WP_Upgrader {
 	 * @access public
 	 */
 	public function generic_strings() {
-		$this->strings['bad_request'] = __('Invalid Data provided.');
+		$this->strings['bad_request'] = __('Invalid data provided.');
 		$this->strings['fs_unavailable'] = __('Could not access filesystem.');
 		$this->strings['fs_error'] = __('Filesystem error.');
-		$this->strings['fs_no_root_dir'] = __('Unable to locate WordPress Root directory.');
-		$this->strings['fs_no_content_dir'] = __('Unable to locate WordPress Content directory (wp-content).');
-		$this->strings['fs_no_plugins_dir'] = __('Unable to locate WordPress Plugin directory.');
-		$this->strings['fs_no_themes_dir'] = __('Unable to locate WordPress Theme directory.');
+		$this->strings['fs_no_root_dir'] = __('Unable to locate WordPress root directory.');
+		$this->strings['fs_no_content_dir'] = __('Unable to locate WordPress content directory (wp-content).');
+		$this->strings['fs_no_plugins_dir'] = __('Unable to locate WordPress plugin directory.');
+		$this->strings['fs_no_themes_dir'] = __('Unable to locate WordPress theme directory.');
 		/* translators: %s: directory name */
 		$this->strings['fs_no_folder'] = __('Unable to locate needed folder (%s).');
 
diff --git a/src/wp-admin/includes/plugin.php b/src/wp-admin/includes/plugin.php
index d881d2918c..0d62aecad2 100644
--- a/src/wp-admin/includes/plugin.php
+++ b/src/wp-admin/includes/plugin.php
@@ -818,7 +818,7 @@ function delete_plugins( $plugins, $deprecated = '' ) {
 	// Get the base plugin folder.
 	$plugins_dir = $wp_filesystem->wp_plugins_dir();
 	if ( empty( $plugins_dir ) ) {
-		return new WP_Error( 'fs_no_plugins_dir', __( 'Unable to locate WordPress Plugin directory.' ) );
+		return new WP_Error( 'fs_no_plugins_dir', __( 'Unable to locate WordPress plugin directory.' ) );
 	}
 
 	$plugins_dir = trailingslashit( $plugins_dir );
diff --git a/src/wp-admin/includes/theme.php b/src/wp-admin/includes/theme.php
index cbfe13540b..6f25348280 100644
--- a/src/wp-admin/includes/theme.php
+++ b/src/wp-admin/includes/theme.php
@@ -60,7 +60,7 @@ function delete_theme($stylesheet, $redirect = '') {
 	// Get the base plugin folder.
 	$themes_dir = $wp_filesystem->wp_themes_dir();
 	if ( empty( $themes_dir ) ) {
-		return new WP_Error( 'fs_no_themes_dir', __( 'Unable to locate WordPress Theme directory.' ) );
+		return new WP_Error( 'fs_no_themes_dir', __( 'Unable to locate WordPress theme directory.' ) );
 	}
 
 	$themes_dir = trailingslashit( $themes_dir );