The official language is Arabic. Knowing a few words is usually a good idea (“hello”, “thank you” etc.). Surprisingly, a large percentage of individuals can communicate in (very) basic English. It is, nevertheless, useful to understand basic Arabic numerals in order to bargain for cab rates. Personnel dealing with foreign visitors (such as tourist hotels, restaurants, tour guides, and so on) can usually converse in English quite effectively.
Because the general population lacks the capacity to converse in English beyond simple phrases, Syria is an excellent location to push yourself to study Arabic via immersion if you want to enhance your Arabic skills.