Advisors to Yasser Arafat are announcing that the PLO leader will deliver an important speech today, marking the end of the festive Muslim month of Ramadan. The PLO officials say that Yasser Arafat will call on Arabs to lay down their arms and end all warfare with the State of Israel. But, diplomatic sources in Israel no longer relate seriously to announcements by Yasser Arafat. \"In the last year alone, Arafat has made many declarations which remained just that, declarations,\" says one Israeli leader in response to the rumors of a significant Arafat statement. Israeli government officials are saying that they will judge Arafat by his actions, and not by his words.