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).
What's the function of وَ in the saying: كُلُّ عامٍ وَأَنْتُمْ بِخَيْرٍ? It is a dubious one. Most grammarians say that you don't need the وَ and that it would be of better Arabic style to skip it! Let's see why.
Reading grammar books in Arabic can be challenging if you cannot decode the language of the grammarians (i'rab إعراب). But there is a formula.
The question of the wasp or hornet - Masʾalat al-Zunbur (مَسْأَلة الزُّنْبُور) - caused Sibawayhi, the most famous Arabic grammarian, to die of anger.