Egyptian Arabic vs Modern Standard Arabic

Not really a question of intelligibility: Fusha is the shared written standard and every educated Arabic speaker reads it, but nobody grows up speaking it. Egyptian Arabic is what people actually say. The two coexist — an Egyptian will read a newspaper in Fusha and then discuss it in Masri.

The differences, side by side

Egyptian ArabicModern Standard Arabic
The letter قGlottal stop — قلم is said alamPronounced as a full q — قلب is qalb
The letter جHard g — جميل is gamiilSoft j — جميل is jamiil
Present tenseb- prefix: باكتب (baktib), "I write"Bare imperfect: أكتب (aktub), "I write"
Future tenseha- prefix: هاكتب (haktib), "I will write"سـ or سوف: سأكتب (sa-aktub)
Negationما...ش around the verb: makatabtishلا / لم / ما before the verb: لا أكتب
"What?"إيه (eeh)ماذا (maadhaa)
"Now"دلوقتي (dilwa2ti)الآن (al-aan)
"I want"عايز (3ayez) / عايزة (3ayza)أريد (ureed)
"Good"كويس (kwayyes)جيّد (jayyid)

The same phrases in both

EnglishEgyptian ArabicModern Standard Arabic
helloأهلا ahlanمرحبا mar7aban
how are you?ازيك؟ ezzayyak?كيف حالك؟ kayfa 7aluka?
thank youشكرا shukranشكرا shukran
happy birthdayكل سنة وانت طيب kull sana w inta tayyibعيد ميلاد سعيد 3eed meelaad sa3eed
good morningصباح الخير saba7 el kheirصباح الخير saba7u al-khayr
good eveningمساء الخير masa el kheerمساء الخير masaa' al-khayr
goodbyeمع السلامة ma3a el salamaإلى اللقاء ila al-liqa'
pleaseلو سمحت law sama7tمن فضلك min fadlika

Which one should you learn?

Egyptian Arabic if you want conversation. Fusha if you want to read books, follow the news, study the Quran, or work in a formal setting. Many learners do Fusha for the sound system and the script, then move to a dialect for speaking.