More than 400 ATMs, which give spoken instructions, went live on Thursday and over 2,000 machines should have the facility by the end of 2014, the Co-op said. People can use the machines by plugging a headset into the ATM and the service will be open to Link and Visa card holders from all banks.
The service will eventually be made available in all the Co-op's bank branches and at most ATMs at Co-operative Food stores.
The Co-op declined to give a figure for the cost of the ATM upgrades, saying it was an "ongoing investment".
The Co-op, which has 2,700 ATMs across the country, expected more than 1,000 of them to have the new function by the end of the year. High-contrast screens are also being introduced to help partially-sighted customers.
David Fawell, head of payments at the Co-operative Bank, said: "We are committed to implementing talking and high contrast services on our cash machines.
"We have started the roll-out and by the end of 2013 we'll have 1,000 of our ATMs enabled to 'talk'. Our aim is to extend this out to over 2,000 cash machines which is three-quarters of our entire estate by the end of 2014."
NatWest has already committed to making 80% of 4,800 cash machines which are branded with its name or that of its sister bank Royal Bank of Scotland (RBS) speech-enabled over the next couple of years.
The Co-op quoted one if its customers, named Mark Ellis, who has campaigned on the issue. Mr Ellis, who is from Colchester, said: "I feel it's compulsory for banks to assist their blind or partially-sighted customers and I hope more will commit to launching the ATMs soon."
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