Why did I never realize this

It’s amazing that we can almost hear a sound from a nonword but it makes sense

It actually makes three little sounds in my head

Really?
This is interesting. Can you try to describe them?

Totally not :D
Don't you 'hear' it as three parts?

No. I 'hear' a single one. The extra question marks just make it stronger.

So, as best I can write it, one would be "mm?"
Two would be, "mM?"
Three is, "mmM?"
Four, "mMM?"
And so on.

For me it’s like three tiny darts hitting a board