It appears that Obama speaks Arabic well according to this 2007 Nicholas Kristoff article in the NY Times .
Obama: Man of the World By NICHOLAS D. KRISTOF
Published: March 6, 2007
He once got in trouble for making faces during Koran study classes in his elementary school, but a president is less likely to stereotype Muslims as fanatics and more likely to be aware of their nationalism if he once studied the Koran with them. Mr. Obama recalled the opening lines of the Arabic call to prayer, reciting them with a first-rate accent. In a remark that seemed delightfully uncalculated. Mr.Obama described the call to prayer as one of the prettiest sounds on Earth at sunset.