diff --git a/wp-includes/class-wp-locale-switcher.php b/wp-includes/class-wp-locale-switcher.php
index 9f1c4831ed..db4ae298c6 100644
--- a/wp-includes/class-wp-locale-switcher.php
+++ b/wp-includes/class-wp-locale-switcher.php
@@ -273,11 +273,12 @@ class WP_Locale_Switcher {
 	 * @since 4.7.0
 	 *
 	 * @global WP_Locale $wp_locale WordPress date and time locale object.
+	 * @global PHPMailer\PHPMailer\PHPMailer $phpmailer
 	 *
 	 * @param string $locale The locale to change to.
 	 */
 	private function change_locale( $locale ) {
-		global $wp_locale;
+		global $wp_locale, $phpmailer;
 
 		$this->load_translations( $locale );
 
@@ -285,6 +286,10 @@ class WP_Locale_Switcher {
 
 		WP_Translation_Controller::get_instance()->set_locale( $locale );
 
+		if ( $phpmailer instanceof WP_PHPMailer ) {
+			$phpmailer->SetLanguage();
+		}
+
 		/**
 		 * Fires when the locale is switched to or restored.
 		 *
diff --git a/wp-includes/class-wp-phpmailer.php b/wp-includes/class-wp-phpmailer.php
new file mode 100644
index 0000000000..b3c976d13d
--- /dev/null
+++ b/wp-includes/class-wp-phpmailer.php
@@ -0,0 +1,93 @@
+<?php
+/**
+ * WordPress PHPMailer class.
+ *
+ * @package WordPress
+ * @since 6.8.0
+ */
+
+/**
+ * WordPress PHPMailer class.
+ *
+ * Overrides the internationalization method in order to use WordPress' instead.
+ *
+ * @since 6.8.0
+ */
+class WP_PHPMailer extends PHPMailer\PHPMailer\PHPMailer {
+
+	/**
+	 * Constructor.
+	 *
+	 * @since 6.8.0
+	 *
+	 * @param bool $exceptions Optional. Whether to throw exceptions for errors. Default false.
+	 */
+	public function __construct( $exceptions = false ) {
+		parent::__construct( $exceptions );
+		$this->SetLanguage();
+	}
+
+	/**
+	 * Defines the error messages using WordPress' internationalization method.
+	 *
+	 * @since 6.8.0
+	 *
+	 * @return true Always returns true.
+	 */
+	public function SetLanguage( $langcode = 'en', $lang_path = '' ) {
+		$error_strings  = array(
+			'authenticate'         => __( 'SMTP Error: Could not authenticate.' ),
+			'buggy_php'            => sprintf(
+				/* translators: 1: mail.add_x_header. 2: php.ini */
+				__(
+					'Your version of PHP is affected by a bug that may result in corrupted messages. To fix it, switch to sending using SMTP, disable the %1$s option in your %2$s, or switch to MacOS or Linux, or upgrade your PHP version.'
+				),
+				'mail.add_x_header',
+				'php.ini'
+			),
+			'connect_host'         => __( 'SMTP Error: Could not connect to SMTP host.' ),
+			'data_not_accepted'    => __( 'SMTP Error: data not accepted.' ),
+			'empty_message'        => __( 'Message body empty' ),
+			/* translators: There is a space after the colon. */
+			'encoding'             => __( 'Unknown encoding: ' ),
+			/* translators: There is a space after the colon. */
+			'execute'              => __( 'Could not execute: ' ),
+			/* translators: There is a space after the colon. */
+			'extension_missing'    => __( 'Extension missing: ' ),
+			/* translators: There is a space after the colon. */
+			'file_access'          => __( 'Could not access file: ' ),
+			/* translators: There is a space after the colon. */
+			'file_open'            => __( 'File Error: Could not open file: ' ),
+			/* translators: There is a space after the colon. */
+			'from_failed'          => __( 'The following From address failed: ' ),
+			'instantiate'          => __( 'Could not instantiate mail function.' ),
+			/* translators: There is a space after the colon. */
+			'invalid_address'      => __( 'Invalid address: ' ),
+			'invalid_header'       => __( 'Invalid header name or value' ),
+			/* translators: There is a space after the colon. */
+			'invalid_hostentry'    => __( 'Invalid hostentry: ' ),
+			/* translators: There is a space after the colon. */
+			'invalid_host'         => __( 'Invalid host: ' ),
+			/* translators: There is a space at the beginning. */
+			'mailer_not_supported' => __( ' mailer is not supported.' ),
+			'provide_address'      => __( 'You must provide at least one recipient email address.' ),
+			/* translators: There is a space after the colon. */
+			'recipients_failed'    => __( 'SMTP Error: The following recipients failed: ' ),
+			/* translators: There is a space after the colon. */
+			'signing'              => __( 'Signing Error: ' ),
+			/* translators: There is a space after the colon. */
+			'smtp_code'            => __( 'SMTP code: ' ),
+			/* translators: There is a space after the colon. */
+			'smtp_code_ex'         => __( 'Additional SMTP info: ' ),
+			'smtp_connect_failed'  => __( 'SMTP connect() failed.' ),
+			/* translators: There is a space after the colon. */
+			'smtp_detail'          => __( 'Detail: ' ),
+			/* translators: There is a space after the colon. */
+			'smtp_error'           => __( 'SMTP server error: ' ),
+			/* translators: There is a space after the colon. */
+			'variable_set'         => __( 'Cannot set or reset variable: ' ),
+		);
+		$this->language = $error_strings;
+		return true;
+	}
+}
diff --git a/wp-includes/pluggable.php b/wp-includes/pluggable.php
index d0b2d3602a..42a63fa63d 100644
--- a/wp-includes/pluggable.php
+++ b/wp-includes/pluggable.php
@@ -251,7 +251,8 @@ if ( ! function_exists( 'wp_mail' ) ) :
 			require_once ABSPATH . WPINC . '/PHPMailer/PHPMailer.php';
 			require_once ABSPATH . WPINC . '/PHPMailer/SMTP.php';
 			require_once ABSPATH . WPINC . '/PHPMailer/Exception.php';
-			$phpmailer = new PHPMailer\PHPMailer\PHPMailer( true );
+			require_once ABSPATH . WPINC . '/class-wp-phpmailer.php';
+			$phpmailer = new WP_PHPMailer( true );
 
 			$phpmailer::$validator = static function ( $email ) {
 				return (bool) is_email( $email );
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 481e2a23e6..2e7f360ad8 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.8-alpha-59591';
+$wp_version = '6.8-alpha-59592';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.