"In a recent note I said I would look up the name of a book I read and comment on whether I thought it would be beneficial for non-native parents speaking English to their children.

The book I was thinking of is "Talk With Your Child" by Harvey S. Wiener.  It is aimed at native speakers of English (that is, it is not specifically aimed at non-natives or multilingual families) but taking a second look at it, I see that it is filled with sample conversations.  I think that this
is the kind of book, if it were in German, would help me develop my ability to speak in the foreign language to the child.

It is a long step away from the "Foreign Language for Parents" course that a few of us have fantasized about, but it's a worthwhile read for the material itself.  (It covers specific ways which parents can expand the language they use with their children.)

Here's a *brief* extract from the book