You mean people in the physical world? Like your buds? If your taking DMT you should tell them not to talk to you until you initiate conversation. Whenever my sitter makes a tiny noise, it enters the trip; bending and warping the sound of it as it passes though...Quite distracting.
Now inside the DMT world is another story. The most I've "heard" speech wise, was like alien chatter very echo-like. It was incomprehensible and sounded like some star trek alien language. I always try talking with the beings in this real but they never respond with speech. It's usually feelings, like they're trying to calm me down by communicating love and compassion. I have on occasion tried calling out "Is anyone out there?" in my mind, and usually the trip just continues as it normally would. Usually involving other species.
You'll know when you've broken through, it's nothing like any of the previous experiences assuming you've started on low doses. 50mg was the magic number for me, don't judge breakthroughs by your ability to respond in the physical world. For me, everything just went dark, and it was like a second layer of DMT...There's first layer like a room which kind of blends/materiales around your physical senses and it's all pretty...But then there's another layer where it just gets dark, and, well...Crazy shit going on in the dark room. You'll have a distinct feeling that you've melted away and become part of something else. Your buds will be non existent, you won't even wonder where they went, they're just gone. lol.