sibling effects

[Shelley L. Velleman]

I'm looking for any studies with data (or possible implications) about
the impact of an older sibling with disordered phonology (or language)
on the phonological/language development of a younger sibling (who is
presumably otherwise normally-developing, which is the catch, of course!
-- How can we know for sure?)  Twin studies where one is
delayed/disordered would also be of interest.

Thanks.

Shelley Velleman
(currently @ Univ. of Wales at Bangor)