The number of people who can speak Irish has increased by nearly 90,000, according to the latest figures released by the Central Statistics Office.
The figures are contained in the nationwide census conducted in April last year and released today.
More than 1.66 million people were able to speak Irish in 2006 compared with 1.57 million at the time of the previous census in 2002.
But only 40% of this number actually use the language.
In percentage terms, there was a slight decline from 42.8% to 41.9%.
Ability to speak Irish was higher among women than men.
Of the towns with a population of 1,500 or more, An Daingean in West Kerry had the highest proportion of Irish speakers.
There was bitter controversy in the town recently regarding the use of its Irish name.
