I have never noticed that she mixes up words at all. No issues with phonics. Self-taught reader. Flawless and fast. Very precocious verbally, in fact, as a toddler. So that part doesn't fit. But, although she has always talked a lot, she would still miss things. It wasn't that she wasn't reciprocal in conversation, but she does need to have things repeated, and always has. She gets called "spacey" by teachers and instructors. Other children complain that she doesn't seem to hear them or is in her own world. At home I'm afraid we tend to read this more as defiant/intentionally ignoring or oppositional, which it may be--or not. Her teacher brought up inattentive ADD as well (I guess I said this upthread) but we generally have no problems with completion of work. In fact, written work is almost always excellent.
Boy, she is a puzzle.
