Minor nitpick, but something that needs to be corrected: There is no such thing as an "Arduino sketch language"; Arduino sketches are written in C/C++, nothing more, nothing less. Behind the scenes, a pre-compiler does some "magic" and adds in the main() function (which calls setup(), then repeatedly calls loop() in an endless looping construct), plus the Arduino library headers - and a few other minor things.
All of this is done to help beginners feel more comfortable with using the system, as well as to improve development time; even so - a simple template "starting point" sketch could have been included and used, instead of the hidden "magic" - but then that would complicate the teaching of the system for newbies, as you would then have to explain what all the other parts were, first, before you could even get to the coding portion. It's debatable which is better, but it is what it is.
Furthermore, the term "sketch" is nothing more than a "marketing term" - one could call it instead "a program" or "source code" or something similar, and it would mean virtually the same thing. The term "sketch" instead is a name to make the system more approachable for newbies to programming.
Most of all of this, by the way, is historical re-purposing of the Wiring and Processing projects (both open source, IIRC), which I believe both used similar (or same) terminology, with the same goal of making software development and hardware embedding more approachable. However, the boards that were used back then, while superficially similar to the Arduino, were somewhat of a different nature and purpose - and were used as the inspiration to create the Arduino, instead, while parts of those systems (like the similarities with the Processing language constructs, as well as the IDE which came from Wiring) were borrowed.
At least, that's how I understand things; if I am wrong in any of this - please correct me.
