I think it often helps to forget that we're talking about "programming languages," as there's a lot of mystification surrounding them. More simply, they're interfaces into the computer, which allow us to tell the computer what to do.
Programs which help us write programs.
We can immediately see that there are better and worse programs. Some let us think the way we want and offer helpful features; while others impose distractions which have little to do with what we're trying to describe. We prefer to describe games and accounting systems, not what's supposed to go in memory location X.
Why aren't we using machine language and Cobol, if we can help it? Because languages greatly differ in expressive power. The thoughts you can conveniently express without fighting the language.
What features might you want?
* Incrementally building your program. Why can't you modify a
running program, and immediately see the changes you made? Maybe
this implies a style where you create a minimal program that
does almost nothing, and build upon it while it's running. A
helpful prompt could let you ask questions and interact with
the program.
* Save and reload your running program "image" like a computer
game.
* Being able to extend the language itself. In English, we create
new idioms all the time. But in languages like C and Python, you
have to wait for central language designers to supply some
trivial new "for loop." The problem is, the central language
designer is probably no expert on your domain. So you need to
cleanly be able to add new extensions to the language, in a way
which doesn't step on other peoples' toes.
* The computer can do menial labor, so the human is liberated to
do what she wants. Like garbage collection.
Among other features. Paul Graham is a notable exponent of such ideas: http://lib.store.yahoo.net/lib/paulgraham/bbnexcerpts.txt http://www.paulgraham.com/avg.html
And Alan Kay, developer of Smalltalk and (I believe) heavily involved with One Laptop Per Child, claimed that "the computer revolution hasn't happened yet." http://video.google.com/videoplay?docid=-2950949730059754521
Tayssir