Talking to someone, talking at someone and talking with someone are the three basic ways in which we communicate, we meaning me.
Talking at someone:
When you listen to my podcast, the voice in which I speak is me talking at you. When you talk at somebody, you are in the voice of a general giving orders to his soldiers. You are the authority and the content of your message is not up for debate. Women are extremely turned off by being talked at unless you say it in a humorous manner for example you tell a gal "Who's your Daddy". Depending on what tone you use, it could be taken as a dominant statement or a humorous statement in which you are exerting your dominance in an entertaining manner.
Talking to someone:
Talking to someone takes their emotions into consideration, but delivers a message that is not up for debate. For example, the professor talks to his class and may adjust his tone to appeal to a broadest audience possible. Basically, when you are talking to someone you are practicing the art of being socially intelligent. You are making sure your message is not lost in someone's hurt feelings. Many great leaders talk to someone. They may occasionally talk at them, but they will vary their tone and inflection depending on the situation.
Talking with someone:
If you are being interviewed on the radio, this is a perfect example of talking with someone. They may ask you questions, but you are catering to what will bring the audience most value first and your voice second. This may mean you break character or what people perceive of you because they hear you talking a specific way in a song or on a podcast when you are by yourself. The voice you use will be on a sliding scale relative to how your audience or whomever you are speaking to responds to you.