You throw a rock into the pond and create a ripple of waves. The waves move outwards from where the rock hit. When the waves pass the wood, it bobs up and down. The wood does not move in the same direction as the wave is moving, but rather it moves in a direction perpendicular to the travel of the wave, i.e. transverse . In the case of the falling dominoes, the movement of the dominoes was in the direction parallel to the movement of the wave, i.e. longitudinal .
Sound waves are longitudinal.
When we speak, the vocal cords vibrate the air, setting it into motion. The molecules of air vibrate in the same direction as the vibration of your vocal cords. These molecules in turn vibrate the molecules next to them, and so on. The region in which the molecules get pushed becomes more dense then the region around it, because more molecules are there. The increased density pushes these neighboring molecules further ahead and the sound travels.