<StringAnimationUsingKeyFrames Storyboard.TargetName="Status" Storyboard.TargetProperty="(TextBlock.Text)">
    <DiscreteStringKeyFrame KeyTime="00:00:00" Value="{noesis:Loc Text.Key.Here}"/>
</StringAnimationUsingKeyFrames>

<DataTemplate>
  <Grid>
    <TextBlock x:Name="txt1" Text="{noesis:Loc Option1Text}" Visibility="Visible"/>
    <TextBlock x:Name="txt2" Text="{noesis:Loc Option2Text}" Visibility="Collapsed"/>
  </Grid>
  <DataTemplate.Triggers>
    <DataTrigger Binding="{Binding Option}" Value="Option2">
      <Setter TargetName="txt1" Property="Visibility" Value="Collapsed"/>
      <Setter TargetName="txt2" Property="Visibility" Value="Visible"/>
    </DataTrigger>
  </DataTemplate.Triggers>
</DataTemplate>

[ContentProperty(nameof(Key))]
    public class TranslateExtension : MarkupExtension
    {
        public string Key { get; set; }
        
        public override object ProvideValue(IServiceProvider serviceProvider)
        {
            try
            {
                // Your language service that triggers an event when the Culture is changed. Here we're using a ServiceLocator to get it
                // but it can just be a singleton
                var languageService = ServiceLocator.Instance?.GetService<ILanguageService>();
                
                if (languageService == null)
                    return Key;

                // If serviceProvider is already a Binding, just return the translation directly
                if (serviceProvider is IProvideValueTarget provideValueTarget && provideValueTarget.TargetObject is BindingBase)
                {
                    var result = TextResources.ResourceManager.GetString(Key);
                    return result;
                }

                // Create a Binding to a a new LocalizedString.Value and return it
                var binding = new Binding(nameof(LocalizedString.Value))
                {
                    Source = new LocalizedString(Key, languageService)
                };

                return binding.ProvideValue(serviceProvider);
            }
            catch
            {
                return Key;
            }
        }
    }
    
    public class LocalizedString : INotifyPropertyChanged                        
    {
        private static readonly WeakEventManager WeakEventManager = new();

        public LocalizedString(string key, ILanguageService languageService)
        {
            Key = key;

            // We're using a WeakEventManager to listen to the Culture change event, you can use any event bus/messaging system
            WeakEventManager.AddWeakEventListener<ILanguageService, LanguageChangedEventArgs>(languageService, nameof(languageService.LanguageChanged), OnLanguageChanged);

            SetValue();
        }

        private void SetValue()
        {
            // Get the localized string value, here we're using our ResourceManager that knows the current culture (via CultureInfo.CurrentCulture)
            Value = TextResources.ResourceManager.GetString(Key);
        }

        public string Key { get; }

        public string Value { get; private set; }

        private void OnLanguageChanged(object sender, LanguageChangedEventArgs e)
        {
            // If the culture changes, we reset the value and trigger PropertyChanged event so the UI will update itself
            SetValue();
            OnPropertyChanged(nameof(Value));
        }

        public event PropertyChangedEventHandler PropertyChanged;

        [NotifyPropertyChangedInvocator]
        private void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }

<TextBlock Text="{t:Translate Hello World!}" />