For me there’s two separate participants, a ‘talker’ and a ‘listener’. My mind identifies more with the talker, because that’s the one that has agency. Since there are two participants, both of which are me, I talk in 1st person plural (‘we’ve got to do …’, 'we thought about this earlier’). I stopped being afraid of being alone after I started having an internal dialogue around the age of 11, since having a second participant in the conversation meant I was always in company.
My mind is mostly pretty quiet. My internal monologue is used for figuring stuff out and making observations/giving myself a warning (ie: that person is lying). It doesn’t narrate anything. I only speak first person with myself. I have difficulty remembering my internal monologue so I’ve made it a habit to write down my observations and then synthesize them. Also my internal monologue is quiet and any kind of noise interrupts it.