Can I upgrade to 15 for free getting 14 now?
No. You would have needed to purchase it less that thirty days before version 15 came out.
But 15 is out - it's both announced at top of adobe page, and available for purchase as download too.
I don't install it often enough to remember, but I think you pick the language in one of the installation steps.
It says so in FAQ - but still there are options to purchase in different languages in both retailer and adobe store.
A bit of a contradiction I think.
I found my way - this is how I did:
a) on swedish adobe site I chose Buy now and come to shopping cart, where it says swedish and nothing to select.
b) I chose edit that entry - which I thought was about no of items only it usually is only thing you edit in a shopping cart, but actually allow to select language as well.
So my lack of fantasy is to blaim.
Maybe a separate edit on each item that can be edited would cleared it up right away.
But now I know.