With Sasha Baron Cohen's new movie "Borat" coming out Friday, he has been all over the news. I saw him on the Today show the other day and heard him on Howard Stern today. I've certainly heard Cohen use Hebrew in the past. His most notable use of Hebrew is his mispronounciation of the Hebrew b'vakasha ("thank you") when in character as "Ali G." His "boo-ya-ka-sha" has become a favorite expression for millions of teenagers
As Borat on "Da Ali G. Show," rather than actually sing the Kazakh national anthem at a Savannah Sand Gnats game, he kept on repeating a famous Israeli folk song: (kum bachur atzel ve'tze la'avoda - "get up lazy guy and go to work."
Never have I heard Sasha Baron Cohen use as much Hebrew as he did on the Howard Stern Show today. His Hebrew is actually pretty good! He must have attended a Jewish day school.
Here's the link to the JTA article about Borat's use of Hebrew.