If I'm writing a library to work with a binary format, there is very little English in my head required, let alone written English.

That is a heavily symbolic exercise. I will "read" the spec, but I will not pronounce it in literal audible English in my head (I'm a better reader than that.)

I write Haskell tho so maybe I'm biased. I do not have an inner narrative when programming ever.

I’m not part of any team, I work on my projects alone. I rarely write long-form design documents; usually I either just start coding or write very vague notes that only make sense when combined with what’s in my head.