Answer:
the audience they are speaking to
their situation or historical context
his/her purpose for speaking
Step-by-step explanation:
An author's choice of delivery is based on certain factors which includes (but is not limited to)
the audience they are speaking to, their situation or historical context, their purpose for speaking.
Delivery simply means the way person makes a statement or speech and if the purpose of such speech is to motivate the audience, the speaker may be inclined to speak animatedly, or if the purpose of the speech is to commiserate, then the method of delivery would likely be sombre and sad.