The Inner Voice

I find dialogue interesting, and am often torn between using quotation marks ('Do you have an umbrella?') and a more silent, kind of interior/private thought (I asked her if she had an umbrella and she said 'no').
When there is dialogue, the silence is broken.
I have swathes of paragraphs in my current novel in which I have removed all dialogue. In this way, the reader is firmly in Corus' pov - inside his body and mind - and the outside world is held at arm's length. There's a kind of peace that comes with this, I feel.
When Corus speaks, he and reader are removed from this private, inner sanctum and are forced to interact with the world.
Maybe this helps with bonding? I'm not sure. Perhaps with characterization? Not sure. There's something peculiar happening that feels good though, as though protag and reader are lovers and know each other intimately and that knowledge is theirs and theirs alone.

I use this in my short-story too. I hide my protag's external voice from the reader, but it is still audible to the other characters.
I ask him if he knows where the end is and he asks me when I was born.
In part, this helps out with the power games I use, where Bina (protag) sits silently, playing with a rock, whilst her victim goes through various stages of fear for his survival. I create the interaction such that Bina is in control - her victim's fate is squarely in her hands. By hearing her thoughts - her interior narrative - rather than her external voice, the reader is given no opportunity to vacate her host body (I see the protag as the host that is occupied by the reader - and as the car that rides along the rollercoaster [emotional topography]). In this way, reader and Bina are dominant, together, and share responsibilities.
I don't need to speak to know what I am thinking or want to say. And that is a kind of power.