Index: src/wp-includes/user.php
===================================================================
--- src/wp-includes/user.php	(revision 43572)
+++ src/wp-includes/user.php	(working copy)
@@ -3116,6 +3116,15 @@
 		return;
 	}
 
+	// Localize message content for user; fallback to site default for visitors.
+	if ( ! empty( $request_data->user_id ) ) {
+		$locale = get_user_locale( $request_data->user_id );
+	} else {
+		$locale = get_locale();
+	}
+
+	$switched_locale = switch_to_locale( $locale );
+
 	/**
 	 * Filters the recipient of the data erasure fulfillment notification.
 	 *
@@ -3226,6 +3235,10 @@
 
 	$email_sent = wp_mail( $user_email, $subject, $content );
 
+	if ( $switched_locale ) {
+		restore_previous_locale();
+	}
+
 	if ( $email_sent ) {
 		update_post_meta( $request_id, '_wp_user_notified', true );
 	}