Irish is a Celtic language, which means it is distantly related to Welsh. In distant prehistory, Irish and Welsh were married. Eventually, however, they got a divorce. In the settlement, Welsh got custody of most of the consonants while Irish got custody of most of the vowels.
Anyway, with Saint Patrick’s day coming up—and given the importance of Irish language and folklore to the faery mythology—I was pleased to see a Mental Floss article on “8 Fun Facts About the Irish Langauge” by Akira Okrent.