The setting is modern-day America, give or take a few years. I'm flexible about what state. I have multiple questions, all related. Once I realized I would be posting here, I started recording what I researched, but I'd already done some of my research (semi-fruitfully) beforehand, so I can't give a totally complete record of search terms.
A congenitally-deaf five-year-old from an alternate universe, who has had almost no real exposure to language, has been taken to this universe and left with someone who knows about both universes. Said person wants nothing to do with a child, but (very conveniently) knows a Deaf couple who would absolutely love kids but (cliche alert) can't have biological children. (In fact, they'd been considering adoption already.) The couple are NOT told about the alternate universe thing, just that somebody dumped the kid with their friend. Sounds a lot like a fairy tale, but, this being the real world in the modern day and not actually a fairy tale, they decide to go to the authorities to try to find the parents (good luck with that) or get the proper documents or whatever.
Question #1: So, they go to the police with a kid who neither talks nor understands English in any form, and seems to be deaf, and has no papers whatsoever (in fact, no one even knows his name). What do the police say? The couple, it should be noted, would love to adopt the child in question. Where does he go from there? Is he sent to a foster home, or can he stay with them? (He seems to like the couple, although of course he hardly knows them.) If so, what would have to happen? Basically, walk me through the procedures here step by step, please.
For this question, I've googled the following terms, all without quotes: foster care, abandoned children, foundling, foundlings in America, what happens if a child shows up and nobody knows who they are?
Googling those terms led me to the following Wikipedia articles: Foster care, Child abandonment, Coin-operated locker baby, Baby hatch, Safe-haven law, Foundling hospital
I also found the websites of the Michigan and Oregon DHSs. They weren't helpful, except that I was able to ascertain that the couple would be qualified to be foster parents.
I looked on a couple more blogs, forums.adoption.com and another .gov site.
Finally, I also looked on the little_details ~adoption tag.
Question #2: How fast will he learn to sign now? How fluent can he get and how long will it take? Will he be noticeably awkward ten years down the road? What about reading English? And how much would his own motivation affect that?
For this question, I know I read the Wikipedia article on the critical period hypothesis. I know I also read some stuff that... uh, came in PDF form and gave me a lot of information about Genie and Victor of Aveyron, and mentioned that ability to learn sign language decreased linearly with increasing age at first exposure, but I was only able to find information about toddlers up to four years old or about adolescents, so either too old or too young, and what I found didn't really give me a clear picture of what it would really look like.
Question #3: What's the best way to proceed with educating him? Does he need to know ASL before he can go to school? Will where and if he's sent to school depend on whether he's living with the Deaf couple or some other foster family? If he shows up in the middle of the school year, can he start immediately? What if it's during the summer? Do Deaf schools typically have a summer session? (And are they all residential?)