Maybe one's preference depends on whether one uses speech or braille. Although I known of some blind programmers who won't learn Python because of the indentation, some like it. Some speech users use a piano scale to show indentation. Some use editor settings that transform the source code on load so that blocks are delimited and reformat on save. The EdSharp, developed by a blind programmer, is one such editor.
I've used Graphviz to make relationship diagrams to aid my communication with sighted people. There's an interesting Google Developer Podcast with T.V. Raman where he mentions programming directly in Postscript while he worked at Adobe.
I've used LaTeX for my personal documents (CV etc.) and sighted people have asked me how on earth I managed to produce such a nice document. I wonder how feasible it would be to use Metafont for more intense graphical expressions.
Most blind people use speech output. If braille displays were more affordable perhaps more people would use them. But with the cost of 80-cel displays being roughly double 40-cell displays, how could make an affordable multiline display?
I don't know APL and I'm not currently smart enough for Haskell. My current infatuation for learning is with Scala. When I first started programming in the mid-80's, I was hacking on a COBOL stock-control system on VMS; the braille display I was using at the time didn't do terminal emulation, and this software built screens by outputting VT52 escape sequences. Although I learnt to decode them so that I could check my screens for alignment and spacing etc. I discovered that I could log an interactive session using SET HOST/LOG; I wrote a TECO program to translate these sessions back into a 2-dimensional layout that was much easier to read on my braille display. So, yes I generally like dense languages.
I'm a blind programmer.
I use a 80-character braille display which shows one line of text at a time. My preferred language is Python although some blind programmers dislike it for its syntactic use of indentation. I find that scrolling with the braille display and feeling for the indentations on left gives me a good feel for the shape of a program. I know another programmer who prefers Perl because of its rich use of sigils, although he uses speech synthesis. I prefer to use vim for all types of editing (I hate IDEs although many blind programmers like Eclipse or Visual Studio).
Why do you reckon the feedback blind programmers use as non-tangible BTW?