diff --git a/core/modules/config/src/Tests/LanguageNegotiationFormOverrideTest.php b/core/modules/config/src/Tests/LanguageNegotiationFormOverrideTest.php
index 76b5078..b5289cb 100644
--- a/core/modules/config/src/Tests/LanguageNegotiationFormOverrideTest.php
+++ b/core/modules/config/src/Tests/LanguageNegotiationFormOverrideTest.php
@@ -25,7 +25,7 @@ class LanguageNegotiationFormOverrideTest extends WebTestBase {
   public function testFormWithOverride() {
     $this->drupalLogin($this->rootUser);
     $overridden_value_en = 'whatever';
-    $overridden_value_es = 'lo que sea';
+    $overridden_value_es = 'loquesea';
 
     // Set up an override.
     $settings['config']['language.negotiation']['url']['prefixes'] = (object) array(
@@ -44,11 +44,17 @@ public function testFormWithOverride() {
     $this->drupalGet('admin/config/regional/language/detection/url');
 
     // The language-negotiation form should be found.
-    $this->assertText('Path prefix configuration', 'Language-negotiation form found.');
+    $this->assertText('Path prefix configuration', 'Language-negotiation form found for English.');
 
     // The English override should not be found.
     $this->assertNoFieldByName('prefix[en]', $overridden_value_en, 'Language-negotiation config override not found in English.');
 
+    // Now check the Spanish version of the page for the same thing.
+    $this->drupalGet($overridden_value_es . '/admin/config/regional/language/detection/url');
+
+    // The language-negotiation form should be found.
+    $this->assertText('Path prefix configuration', 'Language-negotiation form found for Spanish using the overridden prefix.');
+
     // The Spanish override should not be found.
     $this->assertNoFieldByName('prefix[es]', $overridden_value_es, 'Language-negotiation config override not found in Spanish.');