RadNotification offers two localizable strings—TitleMenuToolTip and CloseButtonToolTip.
Thus, you can just set them to the desired values and there should be no issues: http://docs.telerik.com/devtools/aspnet-ajax/controls/notification/accessibility-and-internationalization/localization.
You can see this in action in the following demo: http://demos.telerik.com/aspnet-ajax/notification/examples/localization/defaultcs.aspx.
Thus, whether you obtain those strings from a resx file, database or some other logic (e.g., hardcoded as in the demo), is not important, what is important is that you pass the desired value to the control's property.
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