diff --git a/CHANGELOG.adoc b/CHANGELOG.adoc
index 11d8fd3d6..d0ec627d5 100644
--- a/CHANGELOG.adoc
+++ b/CHANGELOG.adoc
@@ -6,6 +6,7 @@ This file documents all notable changes to https://github.com/devonfw/IDEasy[IDE
 
 Release with new features and bugfixes:
 
+* https://github.com/devonfw/IDEasy/issues/2126[#2126]: Fix language dropdown in GUI
 * https://github.com/devonfw/IDEasy/issues/2176[#2176]: Support 7z archive extraction
 * https://github.com/devonfw/IDEasy/issues/2100[#2100]: Fix Python not available for Mac x64
 
diff --git a/gui/src/main/java/com/devonfw/ide/gui/MainController.java b/gui/src/main/java/com/devonfw/ide/gui/MainController.java
index 11e0f4399..6728992af 100644
--- a/gui/src/main/java/com/devonfw/ide/gui/MainController.java
+++ b/gui/src/main/java/com/devonfw/ide/gui/MainController.java
@@ -6,6 +6,7 @@
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+
 import javafx.fxml.FXML;
 import javafx.scene.control.Button;
 import javafx.scene.control.ComboBox;
@@ -76,7 +77,6 @@ private void initialize() {
   }
 
   private void initLanguageComboBox() {
-
     this.languageMap.clear();
     selectedLanguage.getItems().clear();
 
diff --git a/gui/src/main/java/com/devonfw/ide/gui/nls/NlsService.java b/gui/src/main/java/com/devonfw/ide/gui/nls/NlsService.java
index 1378bfc74..be9afc065 100644
--- a/gui/src/main/java/com/devonfw/ide/gui/nls/NlsService.java
+++ b/gui/src/main/java/com/devonfw/ide/gui/nls/NlsService.java
@@ -68,20 +68,23 @@ public class NlsService {
    * @param locale the preferred locale, or {@code null} to use persisted or default locale.
    */
   public NlsService(Locale locale) {
-
+    this.availableLocales = getAvailableLocales();
     initialize(locale);
   }
 
   /**
-   * Initializes the service using an explicit, persisted, or system default locale.
+   * Initializes the service using an explicit, persisted, or system default locale (if applicable) or English as fallback.
    *
    * @param explicitLocale the locale requested by the caller, or {@code null}.
    */
   private void initialize(Locale explicitLocale) {
-
     Locale localeToApply = explicitLocale;
     if (localeToApply == null) {
-      localeToApply = Locale.getDefault();
+      // Locale.getDefault() returns "de_DE" (for systems set to German) which isn't the same as "de"
+      localeToApply = Locale.of(Locale.getDefault().getLanguage());
+      if (!availableLocales.contains(localeToApply)) {
+        localeToApply = Locale.ENGLISH;
+      }
     }
     applyLocale(localeToApply, false);
   }
@@ -240,7 +243,10 @@ private void loadBundle() {
   }
 
   private ResourceBundle loadBundle(Locale locale) {
-
+    // ResourceBundle.getBundle(...) with Locale.ENGLISH would return German properties on system locale = German
+    if (locale.equals(Locale.ENGLISH)) {
+      return ResourceBundle.getBundle(BUNDLE_NAME, Locale.ROOT);
+    }
     return ResourceBundle.getBundle(BUNDLE_NAME, locale);
   }
 
diff --git a/gui/src/test/java/com/devonfw/ide/gui/nls/NlsServiceTest.java b/gui/src/test/java/com/devonfw/ide/gui/nls/NlsServiceTest.java
index 4a59afb25..8b4ccf562 100644
--- a/gui/src/test/java/com/devonfw/ide/gui/nls/NlsServiceTest.java
+++ b/gui/src/test/java/com/devonfw/ide/gui/nls/NlsServiceTest.java
@@ -1,6 +1,7 @@
 package com.devonfw.ide.gui.nls;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.params.provider.Arguments.arguments;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -17,11 +18,15 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.jar.JarEntry;
 import java.util.jar.JarOutputStream;
+import java.util.stream.Stream;
 
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 import com.devonfw.ide.gui.context.IdeGuiStateManager;
 
@@ -56,16 +61,28 @@ public void tearDown() {
     }
   }
 
-  @Test
-  public void testGetInstanceWithLocale() {
-
-    NlsService service = new NlsService(Locale.ENGLISH);
+  @ParameterizedTest
+  @MethodSource("localeProvider")
+  public void testGetInstanceWithLocale(Locale systemLocale, Locale providedLocal, Locale expectedServiceLocal, String expectedString) {
+    Locale.setDefault(systemLocale);
+    NlsService service = new NlsService(providedLocal);
 
-    assertThat(service.getLocale()).isEqualTo(Locale.ENGLISH);
+    assertThat(service.getLocale()).isEqualTo(expectedServiceLocal);
     assertThat(service.getResourceBundle()).isNotNull();
-    assertThat(service.get("CurrentLanguage")).isEqualTo("English (en)");
+    assertThat(service.get("CurrentLanguage")).isEqualTo(expectedString);
   }
 
+  static Stream<Arguments> localeProvider() {
+    return Stream.of(
+        arguments(Locale.GERMANY, Locale.ENGLISH, Locale.ENGLISH, "English (en)"),
+        arguments(Locale.GERMANY, Locale.GERMAN, Locale.GERMAN, "Deutsch (de)"),
+        arguments(Locale.GERMANY, null, Locale.GERMAN, "Deutsch (de)"),
+        arguments(Locale.UK, Locale.ENGLISH, Locale.ENGLISH, "English (en)"),
+        arguments(Locale.UK, Locale.GERMAN, Locale.GERMAN, "Deutsch (de)"),
+        arguments(Locale.UK, null, Locale.ENGLISH, "English (en)"),
+        arguments(Locale.FRANCE, null, Locale.ENGLISH, "English (en)")
+    );
+  }
 
   @Test
   public void testSetLocale() {
@@ -78,7 +95,6 @@ public void testSetLocale() {
     assertThat(service.get("CurrentLanguage")).isEqualTo("Deutsch (de)");
   }
 
-
   @Test
   public void testAllLocalizationBundlesContainExactlyTheEnglishKeys() throws IOException {
 
@@ -147,7 +163,6 @@ public void testSetLocalePersistsSelectionInUserHomeIdeProperties() throws IOExc
     assertThat(properties.getProperty("IDE_OPTIONS")).isEqualTo("-Duser.language=de");
   }
 
-  
   @Test
   public void testPersistLocaleUpdatesExistingUserLangInIdeOptions() throws IOException {
 
@@ -314,6 +329,3 @@ private static void writeJarEntry(JarOutputStream jos, String name) throws IOExc
   }
 
 }
-
-
-