Most people doesn't know much about the Arabic language so i will talk to u little about it.
Arabic is the hardest language to learn & nobody on the earth knows everything about it & if someone know's 50% of it he will be amazing the grammers in arabic is really really complicated, No language has grammers like the arabic grammers, & the Arabic language has something named "The weight of the word" it means in arabic "Alwazn" it's a hard & amazing thing, I can't explane it easly but u can say the words "moon" & "foot" has the same weigh of "play" & "stay" has the same weigh & every word weigh means something, for example: if any word has the "play" weigh that means it's a verb & if we changed the weigh of the word it can be a noun or adverb or anything u want, & every word have the parent word & the parents can have any weigh.
There is a huge book named "Lisan Ul'arab" it contains most arabic "Parent words", it's like the Arabic-Arabic dictionary & this book has more than 10000 page
& I've read a book about the word "Lam" it usually means "Didn't" but it has so so many meanings & that meaning changes sometimes & sometimes it mean's 3 or more meaning at the same time, & that book has 1000 page It's just talk about 1 word & nobody can know everything about any Arabic word, every word can mean more than 10 meanings.
& this thing makes the Arabic language have very short Expressions & very short setences.
All these grammers makes studying Arabic interesting, understanding what an arabic poetry means is like solving a puzzle.
Most languages changes with time except Arabic & every language on the earth took words from Arabic, but Arabic doesn't borrow any word from any language.
for example in english:
Earth took from Arabic they pronounce it in Arabic "Ardh"
Tall took from Arabic they pronounce it in Arabic like "Tool"
Camel took from Arabic they pronounce it in Arabic "Jamal"
As you can see Arabic is like the parent of all the languages.
& that's why Arabs think that Arabic is the best language to use