Wolof and French are the main langugages in Dakar, but there are about 20 ethnic groups in Senegal, all of which have their own unique languages. For example, a friend of mine grew up in Kedougou, a town in southeast Senegal, and speaks Pulaar, one the many ethnic languages.
The West African Franc (CFA) is the currency used here. The same currency is also used in Benin, Burkina Faso, Guinea-Bissau, Ivory Coast, Mali, Niger, and Togo. These countries share the same currency because the French government introduced it during a time in which all of these countries were colonies of France.
A 1 liter bottle of water costs 400 CFA (about 70 cents in the US). This seems cheap, but considering the fact that the tap water is not safe to drink, the cost of water adds up rather quickly.
I had Yassa Poisson, a Senegalese dish consisting of grill fish and a delicious onion sauce. I eat Yassa at least once a week (and I don't mind because it's really tasty).