The talking Dolphins are from the 1999 animated Titanic film The Legend of the Titanic.
When Elizabeth cries over the bow of the ship the Dolphins come and started talking to hear explaining that there talking to her because of some magic moonbeams that caught her tears as they fell into the water. They tell her about how nasty Evarard Maltravers is she then really does not want to marry him. After Tentacles throws the iceberg at the Titanic the dolphins tell him he has threw an iceberg at a ship full of people which makes Tentacles feel upset for what he's done. At the end of the film the dolphins say they have a surprise for all the people and it appears that Tentacles is ok and didn't die after going down with the Titanic.
The Dolphins made two quick cameos in the sequel, In Search of the Titanic. Looking in the bathysphere, and inside the bottom of the new Atlantean restored Titanic at the end.