1.That in written Arabic many of the vowels are not written out. قطر =qtr =qatar. For the longest time I could not understand why people would write things like "msh" when its pronounced "mesh".
2.That there are signifcant differences between arabic dialects and that there are many of them. I would learn words and phrases in fus7a and then read song lyrics, not understanding why so many of the words were totally different. I dont think I can pick 2 words out of a magrebi song.
3.That Khalij is not fus7a
4.That wayn is dialect and ayna is fus7a
5.That unlike hindi, learning the script really is a must if one wants to learn arabic properly. I only admitted defeat last night and accepted i have to do it.
6.Trying to learn words through movies and song lyrics is only moderately helpful. Because unlike other languages, in arabic the single word is modified to reflect different cases. (eg. sadiq=friend, sadiq'ii = my friend). So I might misinterpret 'sadiq'ii to mean 'friend' and not 'my friend' because it is one word.