Now that Newspeak is out for download, I just had to take a look to see what some of my friends in the industry have been up to. There are some great UI innovations in there and the documentation is pretty good. It's great to see what they've done so far.. it smacks of Self (in my opinion, in a bad way) but it's still a very interesting thing to check out if you love programming languages.
One thing I wanted to nitpick on though was to do with inputting data. Someone, somewhere along the way decided that it'd be neat if each field in Newspeak was responsible for itself - very object oriented, sure, except that it's not very user friendly. What am I talking about? Here's a screenshot we'll discuss off of:

Each field has its own accept/reject button. As you change the data, you're expected to tick "yes" to your changes. Consider the alternatives here - the web browser and common dialogs generally have one "yes" button at the bottom, either "Submit" for webpages or "Okay" for dialogs. Consider the alternate alternative - there is no accept button at all.
It was noted many moons ago that Microsoft Word should never ask you to save.. it should just do it for you and never lose your data. The responsibility here then comes back to Undo - specifically unlimited undo, where you can revise all the way back to the very first keystrokes you typed in to your document. There are resourcing limitations to this idea - but on a modern computer, not as many as there were back when this idea was first raised.
So why then, in Newspeak, are we presented with the ultimate opposite of this idea - forcing you to tick each change you make like some sort of buraeucrat. If this was a data entry form with 50 fields on it, you'd drive the data entry monkeys absolutely batty after the first few records. Clicking save after each record is just as annoying.. not having to do anything but enter the data is what you really want.
I'm not saying there aren't unsolved problems with the unlimited undo + no save UI design, but it sure beats clicking yes dozens of times as you fill in data. I agree, the yes/no buttons look cool, but it seems like an oversight in usability to me. Just my 2c.. your opinion on it may differ.