Pope Francis is slowly regaining his strength in hospital but must "relearn to speak" after prolonged use of high-flow oxygen therapy, Cardinal Victor Manuel Fernandez said on Friday (March 21).

The cardinal, who is the head of the Vatican's doctrinal office, dismissed speculation that the pontiff would retire and said he was returning to his old self.

The 88-year-old pope has been hospitalized for five weeks suffering from double pneumonia, during which time the Vatican has released just one brief audio of him speaking, on March 6, when his voice was broken, breathless and hard to understand.

In its latest health update released on Friday, the Vatican said the pope's condition remained stable with "minor improvements in breathing and mobility."

It confirmed he had not used mechanical ventilation for help with breathing at night since Monday, but was rather receiving oxygen via a small hose under his nose for much of the time.

There is still no official word on when he might return home to the Vatican and Fernandez said he did not know if he would be discharged in time for Easter, which falls on April 20.