For example:
What’s the right way to address the Dean of a Cathedral in speech today?
The correct form of address today is ‘Mr Dean’ or ‘Madam Dean’.
However, this is now seen as very formal and rather old fashioned but using it can carry particular significance – perhaps someone is being consciously old fashioned or excessively formal when talking to a Dean; or perhaps the Dean wants to be seen in a certain way and so insists on a certain type of address. Each could be the case, so again it’s very useful for a scriptwriter or an actor to know; if it’s incorrect then it means that any potential significance is lost and it just comes across as wrong.