[name_m]How[/name_m] would you spell a name pronounced [name_u]KAY[/name_u]-ah, like [name_u]Kay[/name_u] with an a on the end of it?
All of the spellings I can think of would get [name_m]KY[/name_m]-ah or KEE-ah.
[name_f]Kaia[/name_f], [name_f]Kaya[/name_f], [name_f]Kaiya[/name_f], [name_m]Kea[/name_m], Kaeh, Kaea, Keya, Keyah… Any ideas?
I’d use a C, probably. Some people might assume Caya rhymes with [name_f]Maya[/name_f], but apart from that I think they’d get right to your pronunciation (and at any rate, once corrected it shouldn’t be an issue).
I knew a girl in elementary school who’s name was Keya pronounced [name_u]Kay[/name_u]-ah. I think I would spell it Keya, [name_f]Kaya[/name_f] or Kaea.
Keia? It rhymes with [name_f]Leia[/name_f]? I’m not sure. But, really, as soon as people figure out the correct pronunciation, it shouldn’t be a problem. [name_f]Kaya[/name_f] looks the best of your list.
What about [name_f]Kayah[/name_f]? Or Kayea?
I looked around online and couldn’t find any spelling that would be exclusively pronounced [name_u]KAY[/name_u]-ah, like you want; so I don’t think there’s a “silver bullet” (so to speak) pronunciation for you. If you want to name you daughter [name_f]Kayah[/name_f], [name_f]Kaya[/name_f] or a variation of that, you’ll have to correct people who say it as [name_u]KAI[/name_u]-ah unfortunately. 
You could name her [name_f]Cadence[/name_f] or [name_f]Kaydence[/name_f] and call her [name_f]Kaya[/name_f], maybe then people would understand how to pronounce it.
[name_f]Kaya[/name_f]. I don’t see how anyone could mispronounce this as the name [name_u]Kay[/name_u] is so well known.
Keya
Keia
Or I agree with spelling it with a C.
Caya
Ceya
I know a girl named [name_f]Kaya[/name_f] pronounced kay-uh, so that spelling seems fine to me
[name_f]Kaya[/name_f] is the most straightforward, but you will definitely have instances where you’ll need to correct people. Kaea might be an alternative.
I feel like Kaeah or Kaea would be your best bet… To me [name_f]Kaia[/name_f], [name_f]Kaya[/name_f], [name_f]Kaiya[/name_f], [name_m]Kea[/name_m], Keya, Keyah, etc would all be “K-EYE-UH”
I quite like the look of Kaea. I love Gaelic names, and this has that same kind of feel to it.
Some people have said [name_f]Kaya[/name_f] seems the most obvious spelling, but to me this looks a bit boring. Also, if [name_f]Maya[/name_f] is said like [name_m]Myer[/name_m] (mot commonly) then [name_f]Kaya[/name_f] will probably be treated the same.
Thanks for all your help! I really like Keia and Kaeya so far, and they’ve gotten the right pronunciation from the people I’ve asked about 75% of the time. So that’s a pretty great passing grade 
I like the look of Kaeya a little bit more, but being able to say “Keia rhymes with [name_f]Leia[/name_f]” seems so helpful and very stress-reducing. What do you think?
I think Kaeya is most likely to get the right pronunciation, otherwise [name_f]Kaya[/name_f]. There are a lot of regional and personal differences in how people pronounce [name_f]Leia[/name_f], too, so that comparison may not help some folks.
I’d just go with [name_f]Kaya[/name_f], it makes the most sense.
Keia seems the most straight-forward to me. I also think it looks nice spelled this way; it reminds me of the Japanese name [name_f]Keiko[/name_f]–which has the same “kay” sound at the beginning. With Kaeya I think you might end up getting another syllable thrown in there sometimes: Ka-ay-uh.
I’m surprised by all the suggestions for [name_f]Kaya[/name_f]–I would definitely imagine this to rhyme with [name_f]Maya[/name_f].
Keia or [name_f]Caia[/name_f] get my votes.
I would definitely spell it [name_f]Kaya[/name_f]. Some people might pronounce it wrong but I think it’s the closest to being pronounce [name_u]Kay[/name_u]-a since it has [name_u]KAY[/name_u] in it.
Kayuh might work, but doesn’t look attractive. [name_f]Kaya[/name_f] is the prettiest option, but I really think you are going to have prn issues with this name.