Dolphins really communicate with each other by means of a language. All the animals have a language to communicate with each other like the elephants, the ants, ... . Perhaps it isn’t an oral language but it can be a communication with something like sounds, ... .
Dolphins help people like Nikki to speak by stimulus. Dolphins are quite animals and this make people feels good. People with neurological diseases, who are in contact with dolphins, wants to communicate with them, so they tryes to speak with them. This method is very useful to treat child’s neurological diseases.
The internet shows webs that say dolphins have really been trained by the US military, but there’re another webs that affirm this idea is wrong.
I have found an interesting site: http://www.dolphinassistedtherapy.com