We know that your more-or-less natural, more-or-less constant wayof speaking is shaped by many things about you including your gender, your ethnicity, where you grew up, your level of education and on and on and on. And then on some more. How you speak is part of your identity. It's who you are. You. You. You. It's all about you, right?
Only partly. How you speak is also all about your context and the people you are talking to.
Here are three recordings of the same person (the fabulous kate!) made within moments of one another. Same Fabulous Kate, same day, same office, same recorder, same message, ... (same linguist looming over her shoulder) with a microphone. What differed was her audience. In all three cases below, Kate was trying to get her addressee to go retrieve a book for her. Listen to the differences in syntax, lexical choice and prosody.