QUOTE (evilgoattea @ Apr 11 2009, 07:43 AM)
Simple question: Can spirits speak?
QUOTE (SR4 @ p.176)
Astral Spirits can also manifest in the same manner as projecting magicians, and many of them prefer this to materialization if they need to interact with a physical person.
QUOTE (SR4 @ p.184)
Manifesting is a psychic effect that allows an astral form to make itself visible and audible on the physical plane through an act of will.
Emphasis mine.
My answer: Yes, spirits can speak and be heard by mundane persons if manifesting or materializing on the physical plane. In fact, speaking/shouting is explicitly mentioned concerning Watcher spirits (SR4, p.181).