The official national language in the United Arab Emirates is Arabic, Emirati people speak the Gulf dialect of Arabic. English is strongly taught as a second language in all schools. Multicultural cities translate into many spoken languages on a daily basis. The major languages spoken in Dubai are Malayalam, Persian, Tamil, Pashto, Bengali, Chinese among many others. But don’t you worry, expats do not usually have the need to learn Arabic.
Most people in the city speak decent English, and with time Arab words are adopted by those who have decided to reside in Middle easter territory. Nevertheless, a word of advice is to learn as much as possible of the local language. Language and culture are intertwined, you can’t truly know one without understanding the other.