You can change the localization of the Telerik controls at runtime in two ways. The first one is to set the static UseDynamicLocalization property of the LocalizationManager to true
before calling the InitializeComponent() method of the application. This way when you change the localization manager's culture, the localized strings of the control will be updated. Keep in mind that this functionality is implemented only for part of our controls. For example, RadGridView and RadScheduleView won't work using this approach. The second one is to reset the template of the control as demonstrated in my previous answer.
To get all Telerik controls in your application, you can subscribe for their Loaded event using EventManager.RegisterClassHandler() method and store them in a collection. Then you can iterate through the collection and reset the templates of all it's elements.
Or you can use the ChildrenOfTypeExtensions.ChildrenOfType<T>() method to get all Telerik controls when you change the culture.
Also, I have created a sample project with several Telerik controls where you can see how to implement these approaches.
Do you want to have your say when we set our development plans? Do you want to know when a feature you care about is added or when a bug fixed? Explore the Telerik Feedback Portal
and vote to affect the priority of the items