Mr Adams said the money was pledged during talks at Hillsborough Castle
Sinn Fein president Gerry Adams has said the government pledged £20m for the development of the Irish language during the Hillsborough Castle talks.
He said some of the money will be given to the Irish Language Broadcast Fund.
It provides over 75 hours of TV in Irish for a number of outlets, including the BBC and TG4.
Culture Minister Nelson McCausland welcomed the investment and said money would also be made available to promote Ulster Scots.
"I welcome money coming into the Northern Ireland economy," he said.
"There's business here for local film and television production companies and anything that brings business to Northern Ireland is bound to be good for Northern Ireland.
"The good news alongside that is that we will now, for the first time, have an Ulster Scots Broadcasting Fund."
Mr McCausland said £5m would initially be given to the Ulster Scots Broadcasting Fund, but said he would be making further announcements in the coming weeks about the fund.
Mr Adams said there was also an additional £8m for capital projects in the fledgling Gaeltacht Quarter in west Belfast.
He said the Irish Language Broadcast Fund had been denied funding by success unionist culture ministers.
However, this deal, which Mr Adams said was negotiated with the prime minister and would not come out of the Executive's budget, will secure its future until 2015, he said.
A senior Sinn Fein source said the party had been negotiating the deal with Gordon Brown for many months and denied it was a so-called side deal related to the negotiations over the devolution of policing and justice.
Mr Adams also said Sinn Fein would continue to hold the government to what he said was its commitment at St Andrews to introduce an Irish Language Act following the refusal of the DUP to do so.