diff --git a/docs/html/preview/preview_toc.cs b/docs/html/preview/preview_toc.cs
index 1829d11226e83..ad8d45f70ec48 100644
--- a/docs/html/preview/preview_toc.cs
+++ b/docs/html/preview/preview_toc.cs
@@ -3,10 +3,12 @@
   <li class="nav-section">
     <div class="nav-section-header empty"><a href="<?cs var:toroot ?>preview/overview.html"
    es-lang="Información general del programa"
+   in-lang="Ikhtisar Program"
    ja-lang="プログラム概要"
    ko-lang="프로그램 개요"
    pt-br-lang="Visão geral do programa"
    ru-lang="Обзор программы"
+   vi-lang="Tổng quan về Chương trình"
    zh-cn-lang="计划概览"
    zh-tw-lang="程式總覽">
    Program Overview</a></div>
@@ -21,10 +23,12 @@
   <li class="nav-section">
     <div class="nav-section-header empty"><a href="<?cs var:toroot ?>preview/setup-sdk.html"
       es-lang="Configurar el SDK de la versión preliminar"
+      in-lang="Menyiapkan Preview"
       ja-lang="Preview SDK のセットアップ"
       ko-lang="미리 보기 SDK 설정하기"
       pt-br-lang="Configuração do Preview SDK"
       ru-lang="Настройка пакета SDK Preview"
+      vi-lang="Kiểm thử trên Thiết bị"
       zh-cn-lang="设置预览版 SDK"
       zh-tw-lang="設定預覽版 SDK">
       Set Up to Develop</a></div>
@@ -33,10 +37,12 @@
   <li class="nav-section">
     <div class="nav-section-header empty"><a href="<?cs var:toroot ?>preview/download.html"
       es-lang="Pruebe en un dispositivo"
+      in-lang="Menguji pada Perangkat"
       ja-lang="デバイス上でテストする"
       ko-lang="기기에서 테스트"
       pt-br-lang="Testar em um dispositivo"
       ru-lang="Тестирование на устройстве"
+      vi-lang="Kiểm thử trên Thiết bị"
       zh-cn-lang="在设备上测试"
       zh-tw-lang="在裝置上測試">
       Test on a Device</a></div>
@@ -46,29 +52,35 @@
   <li class="nav-section">
     <div class="nav-section-header"><a href="<?cs var:toroot ?>preview/behavior-changes.html"
       es-lang="Cambios en los comportamientos"
+      in-lang="Perubahan Perilaku"
       ja-lang="動作の変更点"
       ko-lang="동작 변경"
       pt-br-lang="Mudanças de comportamento"
       ru-lang="Изменения в работе"
+      vi-lang="Các thay đổi Hành vi"
       zh-cn-lang="行为变更"
       zh-tw-lang="行為變更">Behavior Changes
        </a></div>
       <ul>
         <li><a href="<?cs var:toroot ?>preview/features/background-optimization.html"
               es-lang="Optimizaciones en segundo plano"
+              in-lang="Optimisasi Latar Belakang"
               ja-lang="バックグラウンド処理の最適化"
               ko-lang="백그라운드 최적화"
               pt-br-lang="Otimizações em segundo plano"
               ru-lang="Оптимизация фоновых процессов"
+              vi-lang="Tối ưu hóa Chạy ngầm"
               zh-cn-lang="后台优化"
               zh-tw-lang="背景最佳化">Background Optimizations
               </a></li>
         <li><a href="<?cs var:toroot ?>preview/features/multilingual-support.html"
               es-lang="Idioma y configuración regional"
+              in-lang="Bahasa dan Lokal"
               ja-lang="言語とロケール"
               ko-lang="언어 및 로케일"
               pt-br-lang="Idioma e localidade"
               ru-lang="Язык и языковой стандарт"
+              vi-lang="Ngôn ngữ và Bản địa"
               zh-cn-lang="语言和区域设置"
               zh-tw-lang="語言和地區設定">Language and Locale
               </a></li>
@@ -78,10 +90,12 @@
   <li class="nav-section">
     <div class="nav-section-header"><a href="<?cs var:toroot ?>preview/api-overview.html"
       es-lang="Información general de la API"
+      in-lang="Android N untuk Pengembang"
       ja-lang="API の概要"
       ko-lang="API 개요"
       pt-br-lang="Visão geral da API"
       ru-lang="Обзор API-интерфейсов"
+      vi-lang="Android N cho Nhà phát triển"
       zh-cn-lang="API 概览"
       zh-tw-lang="API 總覽">Android N for Developers
       </a></div>
@@ -89,20 +103,24 @@
 
         <li><a href="<?cs var:toroot ?>preview/features/multi-window.html"
               es-lang="Compatibilidad con ventanas múltiples"
+              in-lang="Dukungan Multi-Jendela"
               ja-lang="マルチ ウィンドウのサポート"
               ko-lang="다중 창 지원"
               pt-br-lang="Suporte a várias janelas"
               ru-lang="Поддержка многооконного режима"
+              vi-lang="Hỗ trợ đa cửa sổ"
               zh-cn-lang="多窗口支持"
               zh-tw-lang="多視窗支援">
         Multi-Window Support</a></li>
 
         <li><a href="<?cs var:toroot ?>preview/features/notification-updates.html"
               es-lang="Notificaciones"
+              in-lang="Pemberitahuan"
               ja-lang="通知"
               ko-lang="알림"
               pt-br-lang="Notificações"
               ru-lang="Уведомления"
+              vi-lang="Thông báo"
               zh-cn-lang="通知"
               zh-tw-lang="通知">
         Notifications</a></li>
@@ -112,40 +130,48 @@
 
         <li><a href="<?cs var:toroot ?>preview/features/tv-recording-api.html"
               es-lang="Grabación de TV"
+              in-lang="Perekaman TV"
               ja-lang="TV の録画"
               ko-lang="TV 녹화"
               pt-br-lang="Gravação para TV"
               ru-lang="Запись ТВ"
+              vi-lang="Ghi lại TV"
               zh-cn-lang="TV 录制"
               zh-tw-lang="電視錄製">
         TV Recording</a></li>
 
         <li><a href="<?cs var:toroot ?>preview/features/security-config.html"
               es-lang="Configuración de seguridad de la red"
+              in-lang="Network Security Configuration"
               ja-lang="ネットワーク セキュリティ構成"
               ko-lang="네트워크 보안 구성"
               pt-br-lang="Configurações de segurança de rede"
               ru-lang="Конфигурация сетевой безопасности"
+              vi-lang="Cấu hình Bảo mật mạng"
               zh-cn-lang="网络安全配置"
               zh-tw-lang="網路安全性設定">
         Network Security Configuration</a></li>
 
         <li><a href="<?cs var:toroot ?>preview/features/icu4j-framework.html"
               es-lang="API de ICU4J del framework de Android"
+              in-lang="ICU4J Android Framework API"
               ja-lang="ICU4J Android フレームワーク API"
               ko-lang="ICU4J Android 프레임워크 API"
               pt-br-lang="APIs de estrutura do Android para ICU4J"
               ru-lang="API-интерфейсы ICU4J в платформе Android"
+              vi-lang="API Khuôn khổ Android ICU4J"
               zh-cn-lang="ICU4J Android 框架 API"
               zh-tw-lang="ICU4J Android 架構 API">
         ICU4J Support</a></li>
 
         <li><a href="<?cs var:toroot ?>preview/j8-jack.html"
               es-lang="Funciones del lenguaje Java 8"
+              in-lang="Fitur Bahasa Java 8"
               ja-lang="Java 8 の機能"
               ko-lang="Java 8 언어 기능"
               pt-br-lang="Recursos de linguagem do Java 8"
               ru-lang="Возможности языка Java 8"
+              vi-lang="Tính năng của Ngôn ngữ Java 8"
               zh-cn-lang="Java 8 语言功能"
               zh-tw-lang="Java 8 語言功能">
         Java 8 Language Features</a></li>
@@ -155,10 +181,12 @@
 
         <li><a href="<?cs var:toroot ?>preview/features/scoped-folder-access.html"
               es-lang="Acceso a directorios determinados"
+              in-lang="Scoped Directory Access"
               ja-lang="特定のディレクトリへのアクセス"
               ko-lang="범위가 지정된 디렉터리 액세스"
               pt-br-lang="Acesso a diretórios com escopo"
               ru-lang="Доступ к выделенным каталогам"
+              vi-lang="Truy cập Thư mục theo Phạm vi"
               zh-cn-lang="作用域目录访问"
               zh-tw-lang="限定範圍目錄存取">
         Scoped Directory Access</a></li>
@@ -182,6 +210,7 @@
   <li class="nav-section">
     <div class="nav-section-header empty"><a href="<?cs var:toroot ?>preview/samples.html"
       es-lang="Ejemplos"
+      in-lang="Contoh"
       ja-lang="サンプル"
       ko-lang="샘플"
       pt-br-lang="Exemplos"