diff --git a/src/globals/ext-tests/gettext.php b/src/globals/ext-tests/gettext.php
index f34f487a..b5bc901e 100644
--- a/src/globals/ext-tests/gettext.php
+++ b/src/globals/ext-tests/gettext.php
@@ -4,20 +4,40 @@ declare(strict_types=1);
 
 assert(function_exists('gettext'));
 assert(function_exists('bindtextdomain'));
+assert(function_exists('bind_textdomain_codeset'));
 assert(function_exists('textdomain'));
 
-if (!is_dir('locale/en_US/LC_MESSAGES/')) {
-    mkdir('locale/en_US/LC_MESSAGES/', 0755, true);
+foreach (['en_US', 'en_GB'] as $lc) {
+    $dir = "locale/{$lc}/LC_MESSAGES";
+    if (!is_dir($dir)) {
+        mkdir($dir, 0755, true);
+    }
+    $mo = '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';
+    $path = "{$dir}/test.mo";
+    if (!file_exists($path)) {
+        file_put_contents($path, base64_decode($mo));
+    }
 }
-if (!file_exists('locale/en_US/LC_MESSAGES/test.mo')) {
-    $mo = '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';
-    file_put_contents('locale/en_US/LC_MESSAGES/test.mo', base64_decode($mo));
-}
-putenv('LANG=en_US');
-assert(setlocale(LC_ALL, 'en_US.utf-8') === 'en_US.utf-8');
+
+// Probe for an available English locale
+$candidates = [
+    'en_US.UTF-8', 'en_US.utf8', 'en_US.utf-8', 'en_US',
+    'en_GB.UTF-8', 'en_GB.utf8', 'en_GB.utf-8', 'en_GB',
+    'English_United States.65001', 'English_United States.1252',
+    'English_United Kingdom.65001', 'English_United Kingdom.1252',
+];
+
+$locale = setlocale(LC_ALL, $candidates);
+assert($locale !== false);
+
+putenv('LC_ALL=' . $locale);
+putenv('LANG=' . $locale);
+putenv('LANGUAGE=' . (stripos($locale, 'US') !== false ? 'en_US:en_GB' : 'en_GB:en_US'));
 
 $domain = 'test';
 bindtextdomain($domain, 'locale/');
+bind_textdomain_codeset($domain, 'UTF-8');
 textdomain($domain);
 
-assert(gettext(json_decode('"\u793a\u4f8b"', true)) === 'Example');
+$src = json_decode('"\u793a\u4f8b"', true);
+assert(gettext($src) === 'Example');