Continuity mistake: When Jesse jumps into the pool to ride on Willy's back for the first time he is fully submerged. However, while riding the whale, his hair is dry.
Continuity mistake: When Jesse gives Willy the fish from the market, the fish he throws has no head but when Willy brings it back it does have a head.
Continuity mistake: When Jesse touches Willy for the first time, when the camera angle changes to behind Jesse, his hair is much curlier than before, and is no longer wet.
Continuity mistake: In the end sequence, where willy jumps the wave-breaker/jetty, in one shot Jesse is on the wave-breaker, in the next shot, where willy starts the jump, Jesse's gone. In the next shot Jesse's back.
Continuity mistake: The sky at the end changes several times from being cloudy to clear. Look at the reflection of it when Willy comes over to Jessie in the water. The next shot is cloudy. The jump scene is clear, and then it is sunny.
Continuity mistake: At the beginning when Willy is captured, the sky changes dozens of times. It goes from being overcast to sunny to cloudy.
Answer: While sounds and words can be used to alert orcas and dolphins, they recognize the hand signals and movements as to what to do.
LorgSkyegon