in general (from my point of view), you can classify Arabic accents to 6 major accents. 1) Arabian Gulf. 2) Iraqi. 3) Shami (Syria, Jordan, Lebanon, Palestine). 4) Egyptian. 5) Sudani. 6) Magharibi. In general, for up to 65%, all Arabs can understand each other regardless of what is the accent used. the differences among these accents are in the usage of many words and the way of pronouncing the word (as all of those accents uses Formal words). for each major accent, its easy to understand among it (for example people form Algeria can understand Moroccan - as a Magharibi major accent). Also, Magharibi accent has a lot of French words, Arabian Gulf accent has Persian and Indian Words, others has English or Italian... and so...