Why is there an 'ai' in plaid if it is pronounced "plad"? That's a word that used to trip me up when I was a little tyke. (This time, unlike my previous question, I hope I'm right in saying that this word is an oddity in having an 'ai' pronounced as 'a'.)
Because it's not English — it's from the Gaelic word for blanket.
According to Gaelic pronunciation, "ai" in old Irish is a short 'a' as in gather.
Just like to point out two things:
Plaid comes from Scottish Gaelic:
According to the site that @Martin Beckett provided, Scottish Gaelic pronounces "ai", as short