Gerry Adams is among six TDs brushing up on their Irish language skills at the taxpayers' expense.
More than €16,000 has been spent on an Oireachtas language scheme since the start of last year.
The Sinn Fein leader's use of the cupla focal in the Dail chamber is being aided by the state-funded scheme aimed at helping TDs and senators improve their ability to speak as Gaeilge.
Mr Adams and party colleague Peadar Toibin TD are using the subsidised tuition service which is also available to civil servants and political staff in Leinster House.
A Freedom of Information Act request by the Sunday Times revealed that the two Sinn Fein TDs are joined in classes by Fine Gael deputies Joe O'Reilly and Paul Coghlan and Independent TDs Thomas Pringle and Maureen O'Sullivan.
The classes are being provided in Leinster House by Conradh na Gaeilge, the group that promotes the everyday use of Irish. Language advocates have been critical of the lack of statements in Irish in the Dail.
The classes are provided early in the morning and during lunchtime so as not to clash with the regular business of the Dail.
The Sinn Fein leader has often spoken of his desire to become a better Irish speaker. Taoiseach Enda Kenny and Fianna Fail leader Micheal Martin are highly-proficient in the language.
Opposition politicians, including Mr Adams, recently criticised the appointment of Joe McHugh as Minister for State with responsibility for the Gaeltacht because of his admission that he was not a fluent Irish speaker.
The junior minister spoke recently of taking classes in his native Donegal to improve his command.
Mr Kenny told the Dail in July that new Arts, Heritage and Gaeltacht Minister Heather Humphreys had arranged to take Irish lessons to become "conversationally fluent".
The Taoiseach said she would be setting a good example to others by "demonstrating to a great number of people throughout the country that it is quite easy to learn the Irish language in a short time".
Ms Humphreys has yet to begin her Irish lessons as she said she has been "very busy with work".
Two years ago, the then Transport Minister Leo Varadkar used his summer holidays to brush up on the language on a course in the Donegal Gaeltacht.