Ferguson, 79, required emergency surgery and spent several days in intensive care at Salford Royal Hospital in greater Manchester.
‘One of the first things I said the day after the operation when my family came to see me was [about] my memory,’ Ferguson said at the Glasgow film festival on Saturday following the premiere of a documentary about the Scotsman called Never Give In.
‘I’ve survived with having a great memory all my life. The next week… I lost my voice. I couldn’t get a word out and it was absolutely terrifying.
‘Everything was going through my mind – is my memory going to be back? Am I ever going to speak again?
‘The speech therapist came and told me to write down all the members of my family, of my football team… She asked me questions about animals, fish, birds. Eventually, after 10 days my voice came back.’
Ferguson is widely considered the greatest manager of all time, having won 13 Premier League titles and two Champions Leagues during his extraordinary 26-year stint at Old Trafford.
Since recovering from his health scare, Ferguson has regularly returned to the Theatre of Dreams to attend Manchester United matches.
The Red Devils, now managed by Ferguson’s former player Ole Gunnar Solskjaer, are currently third in the Premier League table and face leaders Manchester City on Sunday afternoon.
Pep Guardiola’s Man City are on the verge of clinching the title, moving 14 points clear of their rivals after winning 21 matches in a row in all competitions.
Ahead of United’s trip to the Etihad, Solskjaer said: ‘It’s always the perfect game to get everyone going again. You get tested against a very good team, in form.
‘As a Manchester United player we know how much this means for our fans. For this team, we’ve had some of our best moments against City, away and at home.
‘We’ve seen how we can do it. You’ve got to defend well, and you’ve got to attack well. When you walk on to the pitch, and you play a team that is in such a good vein of form, you know that you have to perform.
‘The butterflies come into play, you know, the blood is boiling, you’re getting ready, thinking, “This is a test for me and this is a challenge”.
‘These are the challenges you sign up to when you sign for Man United because you perform in these big games, that’s the next step for us.’
Follow Metro Sport across our social channels, on Facebook, Twitter and Instagram.