Communications: Arabic is the official language. However enough people speak English to get by. Internet and cellphone coverage available at the major tourist spots.
Weather: Egypt is a desert, and while the red sea climate is hospitable, the rest of the country gets very hot most of the year. Best to visit during the fall and winter months (October-March).
Money: ATMs, credit cards, and all forms of money are accepted. Just show the money.
Hassles: Politics: avoid demonstrations and debates about sensitive topics or criticize Islam or the current president Sisi. Fair pricing: negotiate very hard for everything, do not settle at half the quoted price but likely at 10-20%. Watch out for petty theft in the big cities.