Arabic is the national language of Oman, and Hindu, Urdu, Swahili and French are also spoken. Arabic dialects are also spoken in Oman, such as Balochi and JIbbali. English is widely accepted as the country’s second language, so expats will not have too much trouble communicating when they arrive.
While it’s always encouraged to learn the native language, expats who have moved to Oman to work will discover that most business in the country is conducted in English. English is also taught as a second language in almost every school, so you shouldn’t have too many problems communicating in general.
Road signs and official notices are mostly in both Arabic and English too, so unless you head far out of the urban areas you will manage fine.
Arabic can be a difficult language to learn, particularly for Westerners, as it is unrelated to Germanic and Romantic languages that they are more accustomed to hearing and learning. Another difficulty is the number of dialects, but this should only pose a real issue when heading out the city.
It’s very possible that your employer will have in-house Arabic lessons available to you, but if not there are a few language schools in Oman. These provide private and group lessons, and depending on your timetable you can opt for various intensive courses.