Can you move?
Can you stay up on your feet?
Can you make a somatic component gesture?
Clearly No.
Can you think?
Can you see?
Can you cast a spell with no components?
Clearly Yes.
Can you speak?
Can you move your eyes?
Can you breathe?
Clearly Boh. They all require some functionality of the muscles, but I guess nobody is ever going to rule you can't breathe in this case. Anyway, from SRD:
A character with Strength 0 falls to the ground and is helpless.
Helpless
Bound, held, sleeping, paralyzed, or unconscious characters are helpless. Enemies can make advantageous attacks against helpless characters, or even deliver a usually lethal coup de grace.
A melee attack against a helpless character is at a +4 bonus on the attack roll (equivalent to attacking a prone target). A ranged attack gets no special bonus. A helpless defender can't use any Dexterity bonus to AC. In fact, his Dexterity score is treated as if it were 0 and his Dexterity modifier to AC were -5 (and a rogue can sneak attack him).
A character with Dexterity 0 is paralyzed.
Paralyzed
A paralyzed character stands rigid and helpless, unable to move or act physically. He has effective Strength and Dexterity scores of 0 but may take purely mental actions.
Str 0 -> Helpless -> Dex (treated as) 0
Dex 0 -> Paralyzed -> Str (treated as) 0
The problem here is the following:
from the SRD, if you are helpless, your Dex is treated as 0, but you are not necessarily paralyzed (your Dex is NOT 0, just treated as...); otherwise, if you were really paralyzed, you could take only mental action even when you're helpless because you are bound, which obviously does not imply you can't talk.
I wonder if the PHB has a better explanation. In the end it seems that Str 0 and Dex 0 should be quite the same (and the latter specifically says you can only take mental actions), but I couldn't disagree if a DM decides that you can speak when Str 0.