Your anecdote seems to support that it's a learned behavior/skill, which tracks for me. I have a very active internal dialogue that's difficult to turn off. I say dialogue instead of monologue because I often make up "other voices" that bounce ideas off each other, and this generally happens without my conscious effort. I think I developed this because as I was growing up I was encouraged to pray regularly, and I was very fanatically religious as a kid so I did so as often as I could. I prayed silently so often in fact that my thoughts were basically a constant one-sided monologue directed to god. Whenever I would daydream or let my imagination wander I would imagine god responding, and eventually the constant monologue became a dialogue. I would work out problems or make decisions by having conversations with an imaginary god. When I stopped believing in god the second voice never went away, I just started recognizing it as my own.

I have ADHD, it's like having talk radio permanently on in my head. Often times I'll have an internal monologue playing on top of internal background music.

Me too. People like you are fascinating to me. When I first found out that everyone thinks differently I went around interrogating everyone I knew about how they think.

I don't have an interior monologue unless Im typing, but I sometimes use my internal "sound system" to play music.

My inner monologue can easily turn into me talking to myself.

So, if you study a map of a building, noticing that it has a kitchen at a certain place, then in go inside the building (without the map), and someone says "go to the kitchen," how do you know where the kitchen is? How do you imagine the paths, rooms, hallways to follow?

If I told you "a pink and brown dog," you can't "see" that dog in your mind at all?

For the longest time I assumed it was just a literary device, not an actual thing anyone really does.

Only 1-3% of people lack the ability to visualize images in their head.

Somewhat related, I recently realized I can't really remember the taste of food at all. I can remember the texture of the food, and whether I liked it or not, but not how it actually tastes. For example, I know I like chocolate but I have no desire to eat it most of the time because I can't remember anything about the taste except for the texture. But once I start eating chocolate and have the taste lingering in my mouth, I find myself craving more of it until the taste fades and I forget what it tasted like again.

If it's a different person than you, then you have a different issue ;-).

Eh, it isn't all the time for most people, and it isn't hard to shut down for most people either.

The key is that it isn't a separate entity, it's just your own mind using words to ideate. Like, you can see the sky and just enjoy the blue, or you can think about the blue in words, if you have that inner voice. People without that voice still have a way of processing and thinking, it just isn't in words, it's more abstract.

The few people I've met that don't think in words do seem to have difficulty in expressing the experience to others though.

God, same. One of my little annoyances in life is that my internal voice is a goddamn motor mouth and I literally CANNOT stop it.

I can stare at a white wall and watch paint dry, and my monologue will start philosophizing about watching paint dry, where the phrase came from, why I'm doing it (to try and silence my internal voice), then go on a wiki walk about how trying not to think about something makes you think about it more and the classic example of telling someone "don't think about a brown bear" makes them think about bears, then I'll start thinking about bears and my monologue is suddenly halfway across the world.

Put me in a sensory deprivation tank, and my internal voice starts ruminating about how Daredevil uses these to sleep, then goes off about fight sequences, and then superhero comics, and whoops I'm halfway across the world.

Even when I'm paying attention and listening, my inner voice is still motoring away, it's just that it's mirroring what is being said to me instead of going on its own wiki walk halfway across the world (though sometimes someone will say something that makes my internal voice go "wait a second, that makes me think of..." and then I stop listening while I go on a wiki walk).

I have ADHD, in case it isn't obvious yet.

Oh I assure you, you would. Try going to sleep with that mf'r just yapping.

Every time?

No.

Easy example; picture an item in your head. Now flip it.

No language necessary or really even applicable.

But to learn that some people never have an inner dialogue...? That sounds so weird.

Apparently. I first learned about this last year when a co-worker told me to listen to my inner voice. I said, " oh yeah, like Sybil or Jiminy cricket?" I thought she was kidding. Then I thought she was crazy. Then 2/3 of my office said they hear it too. People who hear don't believe that other people don't, and vice versa. People are always trying to trick me into saying I hear something by asking me how I know the sound of my husband's voice or recognize a song, or get a song stuck in my head. When I have a song stuck in my head it's just the urge to sing it and there's no music. I can recognize actors by their voice sometimes, but I cannot do impressions or accents at all!

It's like I just "know" the text. It's just in there with no intermediary.

It's basically just you talking to yourself but without actually speaking.