Lebanon is a Francophone country, thus it has two official languages : Arabic and French.
The French influence has declined a lot during recent years though.
We Lebanese speak our own dialect of Arabic slang. It has similar characteristics to the Levant slang but also has a very distinctive pronunciation and phonetics. The Lebanese dialect is smooth, musical, simple, and easier to learn than colloquial Arabic.
Most Lebanese people are bi or even tri lingual. English and French are both spoken fluently all over Lebanon. Many Lebanese people speak other languages like Russian, German, Spanish, Portuguese and Italian, because of the huge Lebanese diaspora around the world. Don't be surprised if you saw Lebanese speaking some African languages as well.
The Lebanese of Armenian origin have their own language, Armenian, but they also know Arabic and English/French.
There is a very small Assyrian/Chaldean/Syriac/Jewish minority. They have preserved their ancient languages but they are are of negligible numbers and have melted into the Lebanese social fiber. Arabic is their main language with French as a second.
Edit : Ok you don't have to yell ...
Arabic 99%
English 70%
French 30%
Armenian 10%