Wound:
Wound has a 50% chance to hit each time you attack. On hit, your opponent's Speed will decrease by X until the end of the battle, where X is a random number from 1 to whatever your Wound stat is. Wounding is not cumulative, so subsequent strikes will not add on top of each other. Whichever Wound hit is larger will go into effect. An opponent can not be wounded for more than half of their starting speed stat.
Wound can be pretty powerful, hence it has so many restrictions. Here's an example to maybe clear things up a bit:
Example Battle 1:
Turn 1= A15 B15: A attacks. Wounds for 3. 0<3. B Speed = 12
Turn 2= A15 B27: B attacks.
Turn 3= A30 B27: A attacks. Wound misses.
Turn 4= A30 B39: B attacks.
Turn 5= A45 B39: A attacks. Wounds for 2. 3>2. No change.
Turn 6= A45 B51: B attacks.
Turn 7= A60 B51: A attacks. Wounds for 8. 3<8. B Speed = 8
Turn 8= A60 B59: A attacks. Wound for 5. 8>5. No change.
Turn 9= A60 B67: B attacks.
Turn 10= A75 B67: A attacks. Wound misses.
Turn 11= A75 B75: B attacks
Turn 12= A90 B75: A attacks
In this example, we have a lot of stuff happening. On Turn 1, A wounds B for 3, lowering B's speed from 15 to 12. On Turn 5, A wounds B for 2, but since they were already wounded for 3, it had no effect on things. On Turn 7, A gets lucky and manages to wound B for 8, their maximum Wounding capability. However, since 8 is more than half of 15, B's speed is only reduced to by 7, leaving it at 8. A then gets another attack on Turn 8 and wounds B for 5, but since they have already been wounded for 8, it has no effect.
Now it may seem that Wound isn't all that great, but looks what happens if you get lucky and Wound your opponent big early on.
Example Battle 2:
Turn 1= A15 B15: A attacks. Wound for 7. B speed =8
Turn 2= A15 B23: B attacks
Turn 3= A30 B23: A attacks.
Turn 4= A30 B31: B attacks.
Turn 5= A45 B31: A attacks.
Turn 6= A45 B39: A attacks
Turn 7= A45 B47: B attacks
Turn 8= A60 B47: A attacks
Turn 9= A60 B55: A attacks
Turn 10= A60 B63: B attacks
Turn 11= A75 B63: A attacks
Turn 12= A75 B71: A attacks
A= 8 attacks, B=4 attacks
This is why not only is Wound highly restrictive, but expensive points wise, costing as much as speed does.