Most of my conversations are me just doing hand motions and hoping the person i'm talking to can figure it out
I’ve had complete (and accurate) arguments and discussions with “people” via my inner monologue. It never ends. And it’s exhausting. But I really don’t know how people process anything without having an inner monologue 
I feel more like I have several internal voices...not like separate personalities or anything; just different facets of my own mind, yelling at each other all the time. ^^ Once upon a time I tried to illustrate it in a comic, but (a) I quickly discovered I hate trying to joke about my life, and (b) the voices kind of have their own nanoculture...like, if you're speaking with a very old friend and 80% of it is inside jokes that would be hard to explain to other people? It's like that...
Anyway, one artistic benefit of this is always knowing how my writing sounds while I'm doing it. Until I learned that not everyone does internal dialogue, that advice about reading your work aloud to make sure it sounds natural never made sense to me. I'd think, "Can't you just hear it in your head? How would you not know...?"
It can be so infuriating sometimes. I';; be in the middle of a conversation then the other person says one word that set me off. All of a sudden, I'm responding with a question that comes out of nowhere from the perspective of the other person. 
I definitely have an inner monologue and talk to myself often. Mostly to work through problems and also imagining how scenes play out. Honestly, I sometimes have a better time by myself, day dreaming or talking to myself than taking to strangers.
My inner monologue won't shut up sometimes. 
Like as I'm typing this, I'm hearing my inner monologue saying it and also telling me what to say next. My imagination is also pretty vivid and sometimes I just go into daydream mode and just sit there thinking of everything under the sun.
Funny thing is I asked my brother one time and I guess he doesn't have an inner monologue. I can't even imagine what it would be like to not hear yourself talk all day (in your head).
Oh, boy! I can't resist these psychological topics!
If what I write is too long, I'll leave a TL;DR at the end.
Here we go:
Having inner monologues might not sound that healthy or reasonable, but if you hear me out, you'll understand why this may be a productive practice:
first: putting thoughts in words is extremely valuable since sometimes we don't get what we're feeling. Yeah, we may feel a mix of emotions, however, we don't get exactly why. We're so concerned about the emotion explosion in itself than asking why we're having a hard time dealing with it. Deconstructing the thoughts in words makes you realize your feelings' motivation, which usually gets clouded by your nerves.
second: having a second voice to debate with is a blessing even if you're alone. This allows you to face contradictory arguments within your line of thought. Once again, as soon as you start monologuing you ask you some questions about a specific concern, and once that question is made, you direct your brain on thinking about answers to that dilemma you may be facing. Even silence might enough to you back in your tracks.
and third (I'll end with this one): this makes you constantly exercise your brain. Everything you think about is making you evolve your rational thinking. Of course, you can imagine silly things here and there, but when you encounter something you can't get over with, this is the point where you start thinking about resolutions. This way, you'll ponder about hypotheses and outcomes, which tends to orchestrate your view about what you should do over what you should not.
TL;DR: Monologues are healthy if done right. You may direct your brain in better ways than you think by putting things in words as you may find solutions that were once clouded in your head.
Still, dialogues are very valuable as well.
To digest something complex you must first deconstruct the idea in simples topics.
That's where our reason is born anyway: within the principle of the doubt.
Who are we to judge badly something so important and productive such as the monologue?
I voted "I'm not sure" because... honestly, I'm unsure?
I do have discernible thoughts but I don't exactly hear them with a voice, like many people seem to describe. Or rather, I don't hear them in my own voice or any other specific voice, it's just... words and sentences appearing in my brain, as neither text nor speech. Does anyone else feel this way or am I just weird?
My train of thought is chaotic and uncontrollable (though that's probably because of ADHD), and rather like talking to myself in my head, it's like having 20 different people talk at the same time and trying to make any sense out of that (falling asleep with that constantly going on is fun 
)... But again, I don't "hear" them. I talk to myself out loud all the time but it's not exactly an "inner" monologue once you verbalize it, lmao.
The only text running through my brain either comes from memories or imaginings of other people (real or fictional) or if I'm reading words written by someone else. From my own voice, it comes when I'm thinking and plotting of something to say or write or if I just think of commentary that I would never type out/say publicly like "Wow, this is bad." It's like playing videos or sound bytes in my head.
Other than that, most of my thoughts come as imagery to me. I don't have a narrator that just goes on and on inside.
I feel like my insecurity and anxiety talks to me whenever I experience something embarrassing or overthink situations, basically scolding myself for the actions I've taken and regretting them. It sucks but it is what it is 
I tend to overthink a lot, thus my inner monologue.
2 months later
It's one of my worst skills, maybe because i'm a pantser when it comes to writing dialogues and monologues. Always envy those who can come out beautiful lengthy monologues like in Beastars.
No, no, not like that. What I was asking was whether or not you have an internal voice. Here's the definition.
My inner monologue shifts between plotting my series, daydreaming that I'm a fierce, warrior queen, and the negative- no one is ever going to love me and I'll never be more than the "lady's maid"/built-in babysitter. (I am trying to improve my self talk but it's hard.)
oh sorry 'bout that. I thought it's about the characters.
I personally don't self-talk like characters, at least not in full sentences.
All the time.
That's how I write screenplays. I simply put myself into the script and "act" the way I want it to look on screen. I imagine every script writer does that though. 
As far as comics, it's the same thing. But you have to keep tabs on your characters, how they act, what they are like, their motivation for each scene, etc. When you know your characters inside and act, you can "act" for them, and make the dialogue POP.
I was bitten by the Hollywood bug early in life and took some acting classes. So, when I have two or more characters that share the screen, I just "act" for all of them. I worked on a TV series project once that featured five men sharing a brother's mansion together, who had just lost his wife, and it was a sitcom. So I had to act out five different people, with completely different characteristics. I had to sit at my desk and envision the scene, and then "play" it out.
It's quite a talent to have and honestly, if you don't mind looking silly about it, I heartily suggest every writer give it a shot. You'll do much better when it comes to dialogue, for sure. 