What would be the primary purpose of the speech?

Effective writing includes audience and purpose. Every single piece of writing you have ever read has been written with two things in mind: audience and purpose. Imagine a mother who leaves a note on the kitchen table for her children, telling them that there's no milk and asking them to buy a pint before she gets home from work. Even a hastily-written note such as this has an audience (the children) and a purpose (to inform and to make a request).