diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -297,6 +297,7 @@
     'PhutilTestCase' => 'infrastructure/testing/PhutilTestCase.php',
     'PhutilTestPhobject' => 'object/__tests__/PhutilTestPhobject.php',
     'PhutilTortureTestDaemon' => 'daemon/torture/PhutilTortureTestDaemon.php',
+    'PhutilTranslatableText' => 'internationalization/PhutilTranslatableText.php',
     'PhutilTranslator' => 'internationalization/PhutilTranslator.php',
     'PhutilTranslatorTestCase' => 'internationalization/__tests__/PhutilTranslatorTestCase.php',
     'PhutilTwitchFuture' => 'future/twitch/PhutilTwitchFuture.php',
@@ -663,6 +664,7 @@
     'PhutilTestCase' => 'ArcanistPhutilTestCase',
     'PhutilTestPhobject' => 'Phobject',
     'PhutilTortureTestDaemon' => 'PhutilDaemon',
+    'PhutilTranslatableText' => 'PhutilSafeHTMLProducerInterface',
     'PhutilTranslatorTestCase' => 'PhutilTestCase',
     'PhutilTwitchFuture' => 'FutureProxy',
     'PhutilTypeCheckException' => 'Exception',
diff --git a/src/internationalization/PhutilTranslatableText.php b/src/internationalization/PhutilTranslatableText.php
new file mode 100644
--- /dev/null
+++ b/src/internationalization/PhutilTranslatableText.php
@@ -0,0 +1,49 @@
+<?php
+
+final class PhutilTranslatableText
+  implements PhutilSafeHTMLProducerInterface {
+
+  private $result;
+  private $argv;
+  private $file;
+  private $line;
+  private $didRenderAsHTML;
+
+  public function __construct($result, array $argv, $file, $line) {
+    $this->result = $result;
+    $this->argv = $argv;
+    $this->file = $file;
+    $this->line = $line;
+  }
+
+  public function __toString() {
+    return (string)$this->result;
+  }
+
+  public function producePhutilSafeHTML() {
+    $this->didRenderAsHTML = true;
+
+    $orig = array(head($this->argv));
+
+    $argv = array();
+    foreach (array_slice($this->argv, 1) as $item) {
+      $argv[] = '?';
+    }
+
+    return phutil_tag(
+      'span',
+      array(
+        'class' => 'pht-translatable pht-translation-none',
+        'data-sigil' => 'pht-translatable',
+        'data-pht' => json_encode(
+          array(
+            'file' => $this->file,
+            'line' => $this->line,
+            'orig' => $orig,
+            'argv' => $argv,
+          )),
+      ),
+      $this->result);
+  }
+
+}
diff --git a/src/internationalization/PhutilTranslator.php b/src/internationalization/PhutilTranslator.php
--- a/src/internationalization/PhutilTranslator.php
+++ b/src/internationalization/PhutilTranslator.php
@@ -9,6 +9,9 @@
   private $language = 'en';
   private $translations = array();
 
+  private $translateMode = false;
+  private $seen = array();
+
   public static function getInstance() {
     if (self::$instance === null) {
       self::$instance = new PhutilTranslator();
@@ -60,6 +63,11 @@
     return $this;
   }
 
+  public function setTranslateMode($translate_mode) {
+    $this->translateMode = $translate_mode;
+    return $this;
+  }
+
   public function translate($text /* , ... */) {
     $translation = idx($this->translations, $text, $text);
     $args = func_get_args();
@@ -100,6 +108,14 @@
       $result = phutil_safe_html($result);
     }
 
+    // If translation mode is enabled, wrap the result in a a translatable text
+    // object.
+    if ($this->translateMode) {
+      list($file, $line) = $this->getFileAndLine();
+      $argv = func_get_args();
+      $result = new PhutilTranslatableText($result, $argv, $file, $line);
+    }
+
     return $result;
   }
 
@@ -154,6 +170,8 @@
    * @return string Formatted and translated date.
    */
   public function translateDate($format, DateTime $date) {
+    $format = (string)$format;
+
     static $format_cache = array();
     if (!isset($format_cache[$format])) {
       $translatable = 'DlSFMaA';
@@ -209,4 +227,14 @@
     return true;
   }
 
+  private function getFileAndLine() {
+    $trace = debug_backtrace();
+    foreach ($trace as $frame) {
+      if (idx($frame, 'function') == 'pht') {
+        return array(idx($frame, 'file'), idx($frame, 'line'));
+      }
+    }
+    return array(null, null);
+  }
+
 }
diff --git a/src/markup/render.php b/src/markup/render.php
--- a/src/markup/render.php
+++ b/src/markup/render.php
@@ -105,7 +105,7 @@
     if ($v === null) {
       continue;
     }
-    $v = phutil_escape_html($v);
+    $v = phutil_escape_html((string)$v);
     $attr_string .= ' '.$k.'="'.$v.'"';
   }
 
diff --git a/src/utils/utf8.php b/src/utils/utf8.php
--- a/src/utils/utf8.php
+++ b/src/utils/utf8.php
@@ -228,6 +228,8 @@
  * @group utf8
  */
 function phutil_utf8v($string) {
+  $string = (string)$string;
+
   $res = array();
   $len = strlen($string);
   $ii = 0;