This might be more for the teachers out there. Once your kid learns to read, are the skills basically transferrable across languages or do you need to start all over again in a new language (if they're still young)?
Background: We're living in France this year and DD is doing some basic reading in school. By the time we get back to the U.S., DD will be almost in Kindergarten and in NYC public schools, she'll be expected to read at a certain level by then. Not sure if I should be doing anything to supplement what she's doing here, if I should just chill and wait until it's closer to the time we go home or what. For now, it looks like the biggest thing is just teaching her that some of the letters make different sounds in English v. French v. Spanish (which we also speak), but I don't know if there's anything else.
Re: Random reading question
Kids in the US are not expected to be able to read when they start kindergarten. Kids typically know how to say the letters, can identify most if not all of them in at least upper case and possible lower case but reading here is something kids learn in kindy and 1st grade typically. Some kids are early readers and do start sooner but that is the exception not the norm. My odler DD is 5 1/2 and in prek this year, she can name most of her letters by site and can write them all when she sees them (copying them) and maybe half or more when you tell her to write the letter. She is just starting to do very basic spelling (she can spell Mom for example). She is working on reading concepts and tries to read but is not there yet.
I would make sure you DD knows her letters in English and not worry about anything beyond that at this point.
Skills do sometimes transfer, but it's more often if they're fluent in the language. Other times, they're so focused on just understanding the language they can't really pay attention to comprehension.
As to what the expectations are in schools, make sure you know just what is expected in schools. They are expected to know a "certain level" when they enter K, but that level tends to just include sight words, knowing how books work and letters. Even those are not deal breakers.
Since you'll be living overseas, will she be in school in France? Some countries don't expect kids to start school until 7.
If she's interested in reading, letters, etc, definitely make sure she has opportunities to learn (starfall.com is a great pre-k website) and practice what she knows, but a lot of the time at her age, it's just learning to love books and be excited about reading. (btw, I do have a literacy background; if you have more specific questions, feel free to PM me)