A people voice is the voice that someone uses when talking to people who aren't their friends. This voice is automatically happy, nicer and sweeter than their normal voice. It is also often more high pitched. This is often the voice people use when answering a telephone or when working in retail. Similiar to the girlfriend voice.
She so used her people voice when she was talking to that customer over there. Did you hear how sweet she was? She never sounds like that normally!
That friend that always sends you a meaningless text after the obvious end of a text conversation, just to get the last text. They do this while totally oblivious to their uncontrollable habit.
OMG, Jan is SUCH a last texter it drives me crazy. The other day, she sent me a text "K" back after I texted her "don't text me, in a meeting." So then I had to dig out my phone again to clear it so it wouldn't keep vibrating for the rest of the meeting!