The Irish Language is known as gaelic and there alphabet is known as Ogham. Gaelic is part of the Goidelic branch of Celtic Languages known as Q-Celtic.
Ogham Language is dated back to the 3rd to 9th century A.D. The language consist of twenty letters








http://www.omniglot.com/writing/irish.htm


http://www.associatedcontent.com/article/691801/ogham_language_a_history_and_description.html