How old those kids are we talking about?
My first time using a computer was in elementary school. I was 6yo and we learned the "Turtle Thing" (Logo), but I had to transfer. I went back to computer lessons and Logo a couple of years later, but this second time didn't last for a month.
I got my first PC when I was 11, oblivious of programming - and many other things. Eventually, "hacking" became a "trend" among some parties at school... I was 14 or 15. I took VB5 classes for half an year. Of course, at first I felt "WOW!" about making forms and buttons and all this stuff... but a month, two months later, you want to do something other than move a butterfly pic and laugh the same old bad joke with a "running YES/NO" button.
I had neither maturity nor proper understanding, at the time, to realize what I wanted in a way more solid than high school noise and nonsense about "invading this and hacking that". As for the lessons, they were more interested in getting paid than actually teaching something for real. "Magical commands" like
static dim x as integer
were needed to make "magic" happen (so the pic moves, the button flees and so on). Frustration started to pile up as well, as my own PC at home would not behave the way it "should". I revised the "enchantment", again and again and again, and my "tutor" would always blame some alleged typo of mine instead of explaining about how config mishaps and even hardware specs could play a role in the issues I'd claimed.
So I got into college to learn CS. All problems solved - well, nope. As
SirDice remarked, Pascal is (were?) commonly thought as "first" language... and of having some weird "educational" purpose. "Fit for teaching/learning, period" was the only explanation I ever got when I asked, and I didn't ask too many times since an year of Logo (in
elementary school) and six months of Visual Basic 5 barely counted as experience with "programming". And then what? I just felt: "Programming sucks!". I don't think like this today, of course, but it was a long and rough path.
I'd rather wish your kids could learn and like it from the very start.
I'd say any language could work. My bad experiences were my own fault and the lack of proper orientation. Don't try to make the kids believe in "magic". Also, no delving at syntax and language specification is needed nor suggested
of course. But there are other, simpler ways of talking about system memory, configuration, interpreters, debugging, and even the language itself (as they will learn the basics and ask for more). Change names, drop formalism, I don't know but
find a way to teach. Leaving them just puzzled and in despair every time the magic do not work as expected could just feel
way worse and be twice as discouraging.
You can fix a configuration mishap for them, or you can say a file was out of place. You will be doing the work at first, of course, but the next time something go wrong, the kids will surely ask for help...
after trying to move, break, fix, hack, crack and phrack whatever they think the problem is. Then, and only then, will they ask for help but not the "help to fix the issue". Rather, the "help to
learn the answer" they couldn't find or deal with by themselves. And if they fail to grasp the meaning of this or that, who cares? They are kids, they have a whole life to fully grasp whatever they really want to.
It could be interesting like a game for them. But no game can be fun if every time they feel a sense of accomplishment by "mastering a skill", the system changes the rules and they're back to square one. The game is fun when you know it's not magic, but even if you're no expert you can at least conjecture, imagine, have but the faintest idea (maybe a wrong one and
that is fine) about what the problem is. And is not your typo nor have you learned "wrong". Their sense of accomplishment will remain there - fairly.
Sorry for a long and roundabout reply but.. it just felt important to say it. As for what language, perhaps it's better for you - and them, in due time, why not? - to decide. AFAIK even CPC BASIC should be possible with emulators (never tried myself though).
Wish for you and the kids to have a nice and enjoyable experience whatever language you decide upon.