Pronounced ky-suh (“[name]Kaj[/name]” rhymes with “eye”) - according to behindthename, a Swedish diminutive of [name]Katarina[/name]. I think it’s pretty, and simple, but not bland. But I’m worried it might seem too weird in the US. What do you think? I also really like [name]Katarina[/name], so maybe it would be better just as a nickname? Also, combos? My current faves are [name]Kajsa[/name] Liadan, [name]Kajsa[/name] [name]Valentina[/name], and [name]Kajsa[/name] [name]Linnaea[/name], but I could use suggestions.
“[name]Kajsa[/name]” to me is reminiscent of “[name]Katya[/name]”. I wouldn’t worry about it being weird if you genuinely like it, though I’d go for an easily pronounceable middle name as a back-up for when she gets older.
That being said I like [name]Kajsa[/name] [name]Linnaea[/name], though I’d go with the traditional spelling of “[name]Linnea[/name]”. It’s a pretty Swedish name, which goes well with your choice of [name]Kajsa[/name], but is familiar enough people won’t struggle with it.
If you’re truly concerned about it, maybe consider “[name]Kaia[/name]” which has a similar sound.
I’ve seen [name]Kaisa[/name] a lot here in Finland, but never spelled with the K, but that makes sense for Swedish seplling. I like [name]Kajsa[/name] [name]Linnaea[/name] and [name]Kajsa[/name] Liadan. I think I do prefer [name]Kaia[/name]/[name]Kaja[/name].
I love the sound, but I think it would have pronunciation problems in the U.S. I personally love languages and was aware that the J in this name wouldn’t have the English J sound, but I still couldn’t figure out how this name would be pronounced until I read your post. Having said that, I do [name]LOVE[/name] the sound now that I know how it’s said. Is there an alternative spelling of it? I think [name]Kaisa[/name] would be much easier to handle (though she may get [name]KAY[/name]-suh quite often).
[name]EDIT[/name]: [name]Just[/name] read the above post. Looks like [name]Kaisa[/name] is a legitimate spelling. That would be my preference, for practical reasons. However, I think [name]Kajsa[/name] looks awesome…just would be such a challenge in the U.S.
I’m Swedish and can’t say much about how it would work in the US, but I like the name. [name]Kajsa[/name] [name]Linnaea[/name]/[name]Linnea[/name] is my favourite of your combos. My neighbours’ daughters are [name]Anna[/name] [name]Linn[/name]éa and [name]Kajsa[/name] [name]Agnes[/name]. 
(And I would consider [name]Kajsa[/name], [name]Cajsa[/name], [name]Kaisa[/name] and Caisa (ordered from most to least common in [name]Sweden[/name]) all legitimate spellings, I have encountered several of each.)
This is how I feel. I think that with Kasja, your daughter could face some issues with spelling. [name]Kaisa[/name] looks better in my opinion. Best of luck!
Thanks everyone. [name]Kaisa[/name] sounds like it could be a good alternative, although I do like [name]Kaia[/name], as well. Does anyone have other combos I could consider, for either?
Sorry I may be a bit late to the party. Searching on here for [name]Kaisa[/name] for suggested sibling names because we have a [name]Kaisa[/name] (in Iowa). She is 3 and I still [name]LOVE[/name] the name and how we spelled it but she gets called “kay-sa” “ka-sy-a” and “ky-za” pretty often. Once people get hear how to say it it is usually fine. I love the [name]Kajsa[/name] spelling but I think people here would not get it at all! Again, still love our choice with [name]Kaisa[/name] and its uniqueness - have only ever met one person who knew another [name]Kaisa[/name].