THE number of pupils taking Irish GCSE exams is falling at a time when the sector is growing rapidly.
Gael Linn, the national organisation that works to foster and promote Irish, said languages need to become an essential part of the curriculum again.
The group carried out an analysis of the numbers choosing Irish at GCSE from 2007 to 2018.
The findings were "a cause of deep concern", it said.
In 2007, there were 2,710 pupils taking the subject compared to 1,814 this year - a drop of more than 30 per cent.
Separate research predicts an almost 100 per cent rise over a 15-year period in children being educated at Irish-medium schools.
In 2006/07, there were 3,660 children at Irish-medium schools. This increased to 5,873 by 2016 and it is predicted that by 2021, there will be 7,220 children receiving education through the medium of Irish - a rise of 97 per cent from 2006.
Réamonn Ó Ciaráin from Gael Linn said he was concerned.
"There are two subjects available in Irish at GCSE; GCSE Irish and GCSE Gaeilge which is usually taken by Irish-medium pupils of which there are approximately 150 per annum," he said.
"The fall in the numbers choosing GCSE Irish is up to 30 per cent since a decision was taken to make languages optional in the national curriculum and at GCSE level across the UK in 2004. Gael Linn raised this issue when it put together a delegation to lobby members of parliament at Westminster late last month."
The group further noted concerns raised by the chief inspector in which she reported a decline in the study of modern languages.
There has been no replacement for the Primary Languages Programme which ended in 2015. It helped 413 primary schools to introduce Irish, Polish or Spanish at Key Stage 1.
Noelle Buick also reported on falling numbers taking languages at GCSE and A-level despite the quality of teaching them being as good or better than other subjects inspected.
"The chief inspector refers to the Northern Ireland Languages Strategy which has not yet been introduced. This strategy has been on the shelf since 2012. Gael Linn has concerns that this languages strategy will be out of date before it is even introduced," Mr Ó Ciaráin said.
"The number of pupils in Irish immersion education has increased again with 6,184 pupils now attending Irish-medium schools in Northern Ireland.
"Noelle Buick recognises in her report how these pupils are benefitting from acquiring additional cognitive and bi-literacy skills compared with pupils in the English medium sector.
"Gael Linn welcomes this validation of Irish immersion education."
