Probably because programming languages require a precision that natural languages do not have, so you end up having english words that only mean a certain form of their meaning, and completely broken grammar (and/or near impossible to implement). At which point, you are just confusing people by saying "it is like english" (or X natural language).
This is some actual code from one of my projects (though written by another contributor):
To transition to monster card gallery:
animate the gallery-transition as a reel animation targeting the transition-container at 8 fps;
wait for main menu input until all animations are complete;
pause for 1000 milliseconds, accepting input;
now the image-ID of the transition-container is the image-ID of the card-container.
Many, many programming languages have been designed to be English-like.
Unless they are specific to a very narrow domain, they generally don't end up doing that very well, and even the best don't help very much, because you still need to use them more precisely than you'd use a natural language.
The closest thing to an english-like language that is successful is probably SQL.
I meant successful at being English like in use, rather than successful as a language for interacting with computers: I think COBOL is less succesful than SQL at the former, mostly for the reasons that its harder to do when you have a less-specific domain.
Of course, it is subjective, and there is plenty of room for disagreement.
Excel compose [
start
show
open file (test-file)
;alerts on
alerts off
;remove worksheet
;close workbook
;goto workbook 1
;go to worksheet #2
;quit
add a new worksheet
;goto cell "B3"
;select rows "1:3"
select "B4"
set value to x
goto cell "B6"
change to "Testing"
select "B7"
set to "=B4 * B5"
select "A5:A9"
change to "=$B$5 * PI()"
set cell 10 2 to 222.22
set 11 2 to 333.33
set cells "C2:C6" to 123
set "D3:E4" "Yeah!"
change "A1" "=B10"
copy "A1:A9" to "B21"
cut "B21:B29" to "A18"
select "A5:A9"
copy
goto cell "C15"
paste
goto cell "D15"
paste values
goto cell "E15"
paste no borders
go to worksheet "Sheet4"
autofilter "A5" on
open file (test-file-2)
copy workbook "pbtest.xls" "A1:C5"
to workbook "test-b.xls" "B2"
goto workbook "test-b.xls"
goto cell "F1"
cur-cell: current column
repeat i 3 [
repeat j 4 [
goto cell j (cur-cell + i - 1)
set to (i * j)
]
]
]
Lingo, the scripting language for Macromedia Director, looked almost exactly like that. It was a real pain in the ass as soon as you tried to do anything more advanced than, say, drawing rectangles.
Great, then all you will need is a human to translate your other contexts you're not sharing with the computer via your voice to an actual programming language.
This would be fun for prototyping. I could just speak to my computer and have it translate my plain english into a working program :)