Unicorn is a programming language designed specifically to teach you how to program. It is quick to code. It is easy to make something interesting happen immediately. It needs no compilers or special software to run. All you need is this webpage. This contains an area to type in the code, an area of the screen for the output, error checking, a description of the language and many sample programs. It also has a complete tutorial, describing every feature of the language, and of the art of programming.
The tutorial is written for adults. Children would probably find the language too hard. If you want to use Unicorn to teach children programming, then I suggest that you read the tutorial yourself, learn the Unicorn language, and then construct your own teaching plan, at the correct level for the children's age. Programming is a sophisticated skill, and deals with abstract thought, so the more complicated features may well be too hard for young children (although It's surprising what children can do!) But any children that can type letters and numbers will be able to write simple programs that, for exaple, put a little person on the screen, and make him walk along a few steps.
The name 'Unicorn' comes from 'UNIque COder with Reduced Notation.' The reduced notation refers to that fact that an instruction in Unicorn (telling the computer to do something) is usually just one letter and one number. Letters can be upper or lower case. There can be spaces or not, as you wish. Most computer languages have complex formats and it is easy to make a mistake when typing an instruction. Since the Unicorn instruction is so simple to type, the would-be programmer can avoid these mistakes so something works right away. He can then concentrate on getting the computer to do what he wants! The Unicorn webpage allows you to list your Unicorn program, which gives a description of what each instruction does, so this reduced notation doesn't make it harder to understand the program.
The current version of Unicorn was completely rewritten in 2014 to be a more powerful language. This involved changing some of the instructions. If anyone still wants to use the old version, then here it is: Old Unicorn. However, this is no longer being maintained, so I strongly advise that you move to the new language, above.