Why is Arabic called a South Semitic language? The reason has to do with the BROKEN PLURAL. Some ideas about that.
The correct vowel endings damma, kasra, fatha in Arabic can be a headache. If you are careless, you could turn verse 9:3 of the Qur'an into blasphemy (kufr).
The question of the wasp or hornet - Masʾala(t) al-Zunbur (مَسْأَلة الزُّنْبُور) - caused Sibawayhi, the most famous Arabic grammarian, to die of anger.
Yes, there are one-letter-words in Arabic. You probably know the word for and وَ. But there is more - the imperative.
Actually, I don't think that anybody has ever counted the number of Arabic roots. Mathematically: 21,952 roots. Practically, you get 6,332 roots.