A computing apparatus includes a display to present human-readable information and a user input facility. A rule data store contains a statement of rules governing prescribed aspects of presenting data upon the display. These aspects include those aspects subject to variation by language whenever the following changes: type of data, and/or nature of user-operation being performed involving the data. A rules engine is configured to implement the rules. One or more common programs are configured to recognize conditions for applying the rules, and in response, to invoke the rules engine.