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
@@ -64,6 +64,7 @@
     'HTTPFutureTransportResponseStatus' => 'future/http/status/HTTPFutureTransportResponseStatus.php',
     'HTTPSFuture' => 'future/http/HTTPSFuture.php',
     'ImmediateFuture' => 'future/ImmediateFuture.php',
+    'LibphutilUSEnglishTranslation' => 'internationalization/translation/LibphutilUSEnglishTranslation.php',
     'LinesOfALarge' => 'filesystem/linesofalarge/LinesOfALarge.php',
     'LinesOfALargeExecFuture' => 'filesystem/linesofalarge/LinesOfALargeExecFuture.php',
     'LinesOfALargeExecFutureTestCase' => 'filesystem/linesofalarge/__tests__/LinesOfALargeExecFutureTestCase.php',
@@ -570,6 +571,7 @@
     'HTTPFutureTransportResponseStatus' => 'HTTPFutureResponseStatus',
     'HTTPSFuture' => 'BaseHTTPFuture',
     'ImmediateFuture' => 'Future',
+    'LibphutilUSEnglishTranslation' => 'PhutilTranslation',
     'LinesOfALarge' => array(
       'Phobject',
       'Iterator',
diff --git a/src/internationalization/translation/LibphutilUSEnglishTranslation.php b/src/internationalization/translation/LibphutilUSEnglishTranslation.php
new file mode 100644
--- /dev/null
+++ b/src/internationalization/translation/LibphutilUSEnglishTranslation.php
@@ -0,0 +1,34 @@
+<?php
+
+final class LibphutilUSEnglishTranslation extends PhutilTranslation {
+
+  public function getLocaleCode() {
+    return 'en_US';
+  }
+
+  protected function getTranslations() {
+    return array(
+      'Daemon was idle for more than %s second(s), scaling pool down.' => array(
+        'Daemon was idle for more than one second, scaling pool down.',
+        'Daemon was idle for more than %s seconds, scaling pool down.',
+      ),
+
+      'Analyzing %s file(s) with %s subprocess(es)...' => array(
+        array(
+          'Analyzing one file with a single subprocess...',
+          'Analyzing %s file with %s subprocesses...',
+        ),
+        array(
+          'Analyzing %s files with a single subprocess...',
+          'Analyzing %s files with %s subprocesses...',
+        ),
+      ),
+
+      '... (%s more byte(s)) ...' => array(
+        '... (%s more byte) ...',
+        '... (%s more bytes) ...',
+      ),
+    );
+  }
+
+}