In Cairo, the most common and versatile way to say "hello" is "As-salamu alaykum", which literally translates to "Peace be upon you." This is the standard greeting across the Muslim world and is used in both formal and informal settings. The appropriate response is "Wa alaykum as-salam" (And upon you be peace). If you are looking for something more casual or uniquely Egyptian, you can say "Ahlan" or "Ahlan wa sahlan", which is similar to "Welcome" or "Hi." Another very popular Cairene greeting is "Sabaah el-kheir" (Good morning) or "Masaa el-kheir" (Good evening). Because Cairo is a cosmopolitan city with a long history of tourism, many locals will also understand and use "Hello" or "Hi," but making the effort to use the local Arabic greetings is highly appreciated and often met with great warmth. If you want to sound like a local friend, you might hear "Ezayyak" (How are you?) used as a greeting among men, or "Ezayyik" when speaking to a woman, which serves as a common conversational opener.