I am not sure the child is exceptional so much as the environment. It depends on what you mean by being able to read. What level of reading?
She has traveled a lot starting at about 6 months, and has been exposed to lots of languages and cultures. She has some Mandarin now, a little German and a lot of Japanese. So I definitely agree that her environment has supported her language acquisition.
When she was 8, she often read the same books that I read, mostly science fiction, some but not all YA. When she was 10 her class read The Oddysey in French. She was always at least a couple years ahead of her peers in reading level.
The parenting/environmental effects fade a lot (but are still present) by adolescence.
While the effects fade, the advantages gained thereby can last. Being ahead of age norm for reading allowed access to more books, and both learning opportunities. More for my kids who were home educated up to 16[1] so had more time to read stuff they chose, than for me. It also formed a liking for reading.
Parental influence can have a lasting impact. My older daughter is now an electronic engineer, which is the result of an interest that started with making circuits with me as a child.
[1] This makes sense in the British system where the usual age for finishing one set of exams (GCSEs) is 16 (which is the end of compulsory school age) and you then do more specialist exams (A levels in my kids case, there are qualifications too) after that.
As far as reading goes she sounds broadly similar to us - including the taste for SF. Did you have problems deciding on whether books were sufficiently age appropriate or not? There were quite a few where I had to balance a book being good with whether it was suitable (mostly because of violence).
We also talked about the books and I tried to give her a summary in advance, including the parts that I thought she might not handle well. She did skip some books based on my summaries.