Classical Attic Greek is a very difficult language.
Each verb has 6 principal parts that can produce over 500 different forms. The syntax is also quite difficult to master, espcially in complex prose like Plato. About three months of memorizing grammar and vocabulary, with four hours a day minimum, is about the least it would take to stumble through a simple dialogue like The Crito, which is usually what they use as a beginner’s text.
Maybe Charlie Gibson could quiz him on Plato's doctrine of μέθεξις in his next interview. They could both get together on the theory of Forms.
There are certain similarities between Obama's ideas and the theory of Communism outlined in The Republic.