By Rory Cellan-Jones Technology correspondent, BBC News

Spinvox has come under fire for using humans rather than voice-recognition technology

The troubled voice-to-text technology firm Spinvox has been given more time to pay back a loan which threatened its survival.

Spinvox is in negotiations with an American speech recognition firm Nuance which may lead to a sale.

The £30m loan, which was due to be repaid this week, was granted earlier this year by an investor.

Now the company has been told that it has until the end of January to find the money.

A source close to the company said Spinvox had been told: "We're not going to put the company into administration over the £30 million."

Call centres

At the weekend a report in the Sunday Times said Spinvox was close to a deal to sell the business to Nuance, one of the world's leading voice technology businesses, for £92m.

Neither company would confirm the story, but one Spinvox insider told the BBC that negotiations had been under way for weeks, with Nuance interested in the British firm's contracts with a number of major international telecoms operators.

In July, the BBC revealed that much of the work of transcribing voice messages was carried out by call centre staff in locations around the world, rather than by its voice-recognition technology.

Spinvox, which made a loss of £47m in 2007, has delayed the publication of its 2008 accounts.

The company founded by Christina Domecq and Daniel Doulton in 2003 grew rapidly and won awards for its technology. But in July it asked staff to take some of their pay in the form of share options to help the company achieve profitability.

In September it emerged that one investor had written down the value of its stake in Spinvox by 90%.

In an annual report to investors, Invesco valued its £759,000 investment in Spinvox at just £76,000, and also revealed that the business had been put up for sale.