Diesel:
The road signs that do exist are in Irish and English but in some places, such as Connemara, they don't always bother with the English. Also, the distances were marked in kilometers but the speed limits were in miles per hour. The speedometer on our rental car was in both miles and kilometers per hour.
Distances on maps were in kilometers (we think) but the maps are, well, impressionistic to say the least. We think their maps were drawn by a man named Monet or perhaps it was Picasso. Sometimes we weren't sure if we were lost or not!
Bev and Jerry