I knew it all along! "Iechyd Da" means "Yarrrrrrr!"

I must share my pirate joke with all of you:

Q: What does a pirate pave the road with?
A: Tarrrrr!
Q: What instrument does a pirate play?
A: The guitarrrrrr!
Q: Where does a pirate go to drink?
A: The barrrrrr!
Q: What does a pirate drive to work?
A: A carrrr!
Q: No - a ship, stupid!

Andrew.