First, a pretest: Read them again, out loud. Then check your pronunciations below:
Yeah, rhymes with wah or waaa (the baby-crying sound)
Used in the lyrics: She loves you yeah, yeah, yeah, yeah! Not familiar with the Beatles? This will help:
Fun Fact: We were not allowed to use "yeah" in my family, growing up,
in response to questions. It was "Yes" or we heard about it (loudly).
(In retrospect, I can't say that I can find fault with that policy.)
Yah, rhymes with bah, as in Bah Humbug, far (if you live in Massachusetts), and Yahoo (as in the Internet company). You will rarely, if ever, spell this word in any written context, so save yourself some trouble and forget this spelling for the rest of your life. It's pretty much used mostly in Germany (I'm mostly kidding; my mom uses it regularly to indicate that she's heard what you've said, as in, "Yah, yah. I'll be waiting for you at the door." She is of German heritage, though, so that explains that.)
Yay, as in "Yay! We won!"
It's easy to spell this one if you use this trick: The next time you need to spell yay, think of a word it rhymes with (May, bay, ray, day, etc.), and you will easily spell it.
Yea means yes in fancy English. "Yea though I walk through the valley of the shadow of death, I fear no evil." It's also used with a hand gesture to indicate size: "Have you seen a little boy? He's yea big."
Yea is a common misspelling of yeah. Personally, I think it's used so infrequently (in writing) that you can afford to misspell it (Unless you're fancy, of course.).
This has been a Public Service Announcement.
I feel better now.