Hard-line unionist party, The Traditional Unionist Voice (TUV), has apologised for branding Irish a "leprechaun language".
The TUV led by former MEP Jim Allister is to hold its annual conference today as it tries to build-on efforts to draw support from the Democratic Unionist Party (DUP).
The TUV is a trenchant critic of the DUP decision to share power with Sinn Fein, but had to apologise after issuing a press release attacking the translation of Stormont government documents into Irish.
The party hit-out at news that Sinn Fein's Minister for Education Caitriona Ruane spent £47,062 on Irish translations, but its press release on the issue read: "TUV Blast Leprechaun Language Waste."
The TUV's vice chair Keith Harbinson, in whose name the statement was issued, has since apologised and said no offence was intended.
But the Alliance Party politician who revealed details of the Education Minister's spending by tabling a question at the Northern Ireland Assembly, said the TUV blunder was an embarrassment.
"This was a despicable and deeply immature comment. The TUV have shown their true colours during this episode," said the Alliance Party's Trevor Lunn.
"They tried to cynically use the answer to my question and all they managed to do was embarrass themselves.
"My question was balanced as it asked about both Irish and Ulster Scots translations and the answer was revealing in that there appears to be little demand for Ulster Scots translation services in this Department."
The Alliance Party representative's Assembly question found that between 2007/08 and 2008/09 the figure spent on Irish translation in the Education Department rose from £13,274 to £47,062.
He said: "I am in favour of the promotion of the Irish language but I am also in favour of value for money, and that was what this question is about."
The TUV said it apologised for its 'leprechaun language' comment and said the remark had only served to distract from the party's opposition to Ms Ruane's spending.
Jim Allister is a former member of the DUP who left the party over its decision to enter power-sharing government with republicans.
In June's European election his party was seen to have eaten into the DUP's support base.
Sinn Fein's Bairbre De Brun topped the poll, a first for a republican candidate in Northern Ireland, with 126,184 votes, representing 26% of the first preference votes.
The Democratic Unionists had previously topped the poll in every European election since 1979.
But after Mr Allister won 66,197 votes, representing 13.7% support, the DUP tally dramatically fell.
The DUP won 18.2% support in this year's Euro poll, a major drop from the 32% it won in the previous European election in 2004.
DUP candidate Diane Dodds took 88,346 votes, winning a seat without reaching the quota.
Mr Allister will today use his party conference to underline its opposition to power-sharing and launch its plans for the next General Election.