Teaching Amy to read and write English

[pne]

I wonder whether (and if so, when and how) to teach Amy to read and write English.

She'll be taught (and, presumably, learn) to read and write German at school, so that part's sorted, but I don't really want her to be illiterate in half of her native languages. And English spelling is complicated enough that I don't know whether just knowing how to read German will let you read English easily, let alon write it.

So I wonder whether to teach her to read and write English myself at some point (and if so, how).

I remember that in Bilingual Children: from Birth to Teens, the author made little reading and writing exercises for his children, in order for them to practise their second language, and I wonder whether I should do something similar eventually.

Suggestions for methods, time to start, or other things?