CARACAS, Venezuela — President Hugo Chávez is famous for speeches that last for hours, and Thursday should have been a special day for the loquacious socialist to let loose. But even with a parade of foreign dignitaries in town to laud him and a large, boisterous crowd on the day he was to be sworn in for a triumphal new term, Mr. Chávez’s silence spoke loudest of all. The country had been warned in advance that Mr. Chávez was too sick to slip on the presidential sash and raise his hand to take the presidential oath. He remained in Cuba, where government officials said he was going through a delicate recuperation from surgery on Dec. 11 for cancer. But in a telling sign of the severity of his illness, Mr. Chávez apparently sent no greeting to the crowds wishing him well. There was no message from him read to the tens of thousands of followers who attended the rally in front of the presidential palace. There was no video or recording from the once-omnipresent president, who has not been seen or heard from directly in a month.