Just a quick return to this thread.
I think I may have already mentioned that Arabic is a language of roots and patterns. Most Arabic words have a triliteral (three-consonant) root running through them, in a certain order, to give the word a basic meaning. There are then different vowels arranged in different patterns to give different meanings to words.
So, kitaab, kitaaba, kataba, kaataba, maktab and kaatib (meanings: book, writing, to write, to write to each other, office & writer) all have the root k, t, b which means something to do with writing.
Here's a video about Lebanese Arabic from a native speaker. See if you can identify the triliteral root of all the words in the lesson …