כֹּל - כָּל - כֻּלּוֹ

Why this strange orthography? Why the word keeps changing the vowels in its every transformation?

Why do we write this word without Vav in most cases? Why in Ktiv Maleh we write כל אחד and not כול אחד? And if we write it without Vav, why the Vav might appear in the phrase זה הכול? And why even then it's considered "optional" and not mandatory?

Kamatz Katan (the Little Kamatz, read as "O" in modern Hebrew) is one of the first confusions every Hebrew student is facing. Why, for God's sake, it's the same sign as Kamatz Gadol (the Big Kamatz, read as "A")? How is the reader supposed to distinguish between them? Can I just learn all the "exceptions" with Kamatz Katan?

Here I'm going to publish articles speaking of everything that is not covered by other sections. Some of the articles might be giving explanations to those who is not complitely satisfied with the quick-and-dirty approach of the "Read-and-Understand" part of this site, neither covered by the beginner's "Speak!" section.