diff --git a/zero/Configuration/ZeroOptions.cs b/zero/Configuration/ZeroOptions.cs
index 483bf31a..d469e274 100644
--- a/zero/Configuration/ZeroOptions.cs
+++ b/zero/Configuration/ZeroOptions.cs
@@ -9,6 +9,9 @@ public class ZeroOptions : IZeroOptions
   /// <inheritdoc />
   public string Version { get; set; }
 
+  /// <inheritdoc />
+  public string Language { get; set; } = "en_US";
+
   /// <inheritdoc />
   public TimeSpan TokenExpiration { get; set; }
 
@@ -43,6 +46,11 @@ public interface IZeroOptions
   /// </summary>
   string Version { get; set; }
 
+  /// <summary>
+  /// ISO Code for language
+  /// </summary>
+  public string Language { get; set; }
+
   /// <summary>
   /// Expiration of a generated change token for an entity
   /// </summary>
diff --git a/zero/Localization/ConfigurationLocalizer.cs b/zero/Localization/ConfigurationLocalizer.cs
index 6e3a9431..4fa20668 100644
--- a/zero/Localization/ConfigurationLocalizer.cs
+++ b/zero/Localization/ConfigurationLocalizer.cs
@@ -8,12 +8,9 @@ public class ConfigurationLocalizer : Localizer
   private IConfiguration _configuration;
 
 
-  public ConfigurationLocalizer(IConfiguration configuration, IOptionsMonitor<LocalizationOptions> options) : base()
+  public ConfigurationLocalizer(IConfiguration configuration, ICultureResolver cultureResolver, IOptionsMonitor<LocalizationOptions> options) : base(cultureResolver)
   {
     _configuration = configuration;
-
-    // set default language
-    Language(_configuration.GetValue<string>("Zero:Localization:Default", "de"));
   }
 
 
diff --git a/zero/Localization/CultureChangeMessage.cs b/zero/Localization/CultureChangeMessage.cs
new file mode 100644
index 00000000..5f73d7f6
--- /dev/null
+++ b/zero/Localization/CultureChangeMessage.cs
@@ -0,0 +1,8 @@
+using System.Globalization;
+
+namespace zero.Localization;
+
+public class CultureChangeMessage : IMessage
+{
+  public CultureInfo Culture { get; set; }
+}
\ No newline at end of file
diff --git a/zero/Localization/CultureResolver.cs b/zero/Localization/CultureResolver.cs
index c612145a..bbf98a8a 100644
--- a/zero/Localization/CultureResolver.cs
+++ b/zero/Localization/CultureResolver.cs
@@ -1,57 +1,117 @@
 using FluentValidation;
+using Microsoft.AspNetCore.Connections.Features;
 using Microsoft.Extensions.Logging;
 using System.Globalization;
+using System.Linq.Expressions;
 using System.Security.Claims;
 
 namespace zero.Localization;
 
 public class CultureResolver : ICultureResolver
 {
+  /// <inheritdoc />
+  public CultureInfo Current { get; protected set; }
+
   protected ILogger<CultureResolver> Logger { get; private set; }
 
+  protected IMessageAggregator MessageAggregator { get; private set; }
 
-  public CultureResolver(ILogger<CultureResolver> logger)
+
+  public CultureResolver(ILogger<CultureResolver> logger, IMessageAggregator messageAggregator)
   {
     Logger = logger;
+    MessageAggregator = messageAggregator;
   }
 
 
   /// <inheritdoc />
   public Task<CultureInfo> Resolve(IZeroContext context)
   {
-    //var session = context.Store.Session();
-    //Language language = await session.Query<Language>().FirstOrDefaultAsync();
-    string isoCode = "de-AT";
+    if (!TryConvert(context.Options.Language, out CultureInfo culture))
+    {
+      culture = CultureInfo.CurrentCulture;
+    }
 
+    Set(culture);
+
+    return Task.FromResult(culture);
+  }
+
+
+  /// <inheritdoc />
+  public bool TryConvert(string isoCode, out CultureInfo culture)
+  {
     try
     {
-      CultureInfo culture = CultureInfo.CreateSpecificCulture(isoCode);
+      culture = CultureInfo.CreateSpecificCulture(isoCode.Replace('_', '-'));
 
       if (culture.ThreeLetterISOLanguageName.IsNullOrEmpty())
       {
         throw new Exception("ThreeLetterISOLanguageName is empty");
       }
+      if (culture.ThreeLetterISOLanguageName == "ivl")
+      {
+        throw new Exception("Invariant language is not allowed");
+      }
 
-      CultureInfo.CurrentCulture = culture;
-      CultureInfo.CurrentUICulture = culture;
-      ValidatorOptions.Global.LanguageManager.Culture = culture;
+      return true;
     }
     catch (Exception ex)
     {
-      Logger.LogError(ex, "Could not create culture from Language code {code}", isoCode);
-      return Task.FromResult(CultureInfo.CurrentCulture);
+      Logger.LogWarning(ex, "Could not create culture from Language code {code}", isoCode);
+      culture = null;
+      return false;
     }
-    
-    return Task.FromResult(CultureInfo.CurrentCulture);
+  }
+
+
+  /// <inheritdoc />
+  public void Set(CultureInfo culture)
+  {
+    CultureInfo.CurrentCulture = culture;
+    CultureInfo.CurrentUICulture = culture;
+    ValidatorOptions.Global.LanguageManager.Culture = culture;
+    Current = culture;
+    MessageAggregator.Publish(new CultureChangeMessage()
+    {
+      Culture = culture
+    });
+  }
+
+
+  /// <inheritdoc />
+  public void Subscribe(Expression<Func<CultureChangeMessage, Task>> handle)
+  {
+    MessageAggregator.Subscribe(handle);
   }
 }
 
 
 public interface ICultureResolver
 {
+  /// <summary>
+  /// Current culture
+  /// </summary>
+  CultureInfo Current { get; }
+
   /// <summary>
   /// Resolves the current application from either the backoffice user (in case it is backoffice request)
   /// or the domain (in case it is frontend request).
   /// </summary>
   Task<CultureInfo> Resolve(IZeroContext context);
+
+  /// <summary>
+  /// Tries to convert an ISO code to a culture
+  /// </summary>
+  bool TryConvert(string isoCode, out CultureInfo culture);
+
+  /// <summary>
+  /// Set a new culture for this request
+  /// </summary>
+  void Set(CultureInfo culture);
+
+  /// <summary>
+  /// Subscribe to culture change
+  /// </summary>
+  void Subscribe(Expression<Func<CultureChangeMessage, Task>> handle);
 }
diff --git a/zero/Localization/Localizer.cs b/zero/Localization/Localizer.cs
index e2956c30..d6f51af2 100644
--- a/zero/Localization/Localizer.cs
+++ b/zero/Localization/Localizer.cs
@@ -1,23 +1,30 @@
 using System.Collections.Concurrent;
+using System.Globalization;
 using System.Reflection;
 
 namespace zero.Localization;
 
 public abstract class Localizer : ILocalizer
 {
-  /// <inheritdoc />
-  public string LanguageCode { get; private set; } = "de";
-
-
   protected ConcurrentDictionary<string, string> Cache { get; private set; } = new();
 
+  protected ICultureResolver CultureResolver { get; private set; }
 
-  /// <inheritdoc />
-  public ILocalizer Language(string languageCode)
+  protected string LanguageCode { get; set; }
+
+
+  public Localizer(ICultureResolver cultureResolver)
   {
-    Cache = new();
-    LanguageCode = languageCode;
-    return this;
+    CultureResolver = cultureResolver;
+    CultureResolver.Subscribe(msg => OnCultureChange(msg.Culture));
+    OnCultureChange(CultureResolver.Current);
+  }
+
+
+  Task OnCultureChange(CultureInfo culture)
+  {
+    LanguageCode = culture.Name.Split(new char[] { '_', '-' })[0];
+    return Task.CompletedTask;
   }
 
 
@@ -97,16 +104,6 @@ public abstract class Localizer : ILocalizer
 
 public interface ILocalizer
 {
-  /// <summary>
-  /// Current language code
-  /// </summary>
-  string LanguageCode { get; }
-
-  /// <summary>
-  /// Set language for localizer
-  /// </summary>
-  ILocalizer Language(string languageCode);
-
   /// <summary>
   /// 
   /// </summary>