I read this book about 10 years ago after I borrowed it from the Teen/YA section of the library.
- A teenage boy moves (possibly to Scotland? That’s ringing a bell) and meets a girl.
- They discover a facility locally where some children live. The book focuses on 3 or 4 children; I don’t know if they are the only ones there.
- They have odd names and bizarre physical traits. IIRC, one has no eyes, and one has wings.
- They have made up words to replace things in our language.
- The doctors who look after them make them watch a lot of documentaries.
- The boy and girl decide they are going to break the children out.