In what instance would speakers vary their speech patterns?

When speaking at a press conference

When answering questions

There are no instances in which speakers would vary their speech patterns.

When they are happy

When giving a formal presentation

When speaking to different audiences (e.g., children vs. adults)

When conveying emotions or emphasis in their speech

When speaking in different social or professional settings

When trying to connect with and engage their listeners

When speaking in a foreign language or to non-native speakers