I think this is true that the dolphins can to communicate each other by means of a language. I read a lot of webs site where explain different experiences about the communications’ dolphins like these. In 1962 Dr. Dreher and Dr. Evans were aboard the research vessel Sea Quest, 300 miles south of San Diego, studying gray whales. They had strung a number of vertical aluminum poles and microphones inside Scammon's Lagoon, erecting a type of barrier. A short time later five Pacific Bottle-nosed dolphins were spotted about 500 yards from the barrier. After a few minutes of what was labeled conversation, a scout was sent from the group. Microphones picked up his sonar soundings as he closely surveyed the poles. When he returned to the pod an explosion of whistles, chirps and Bronx cheer-like noises were recorded via microphones. After several minutes of conversation the dolphins proceeded through the barrier and into the bay.
A similar occurrence was noted when, in 1962, several Lockheed Aircraft Corporation scientists erected a similar barrier across a channel, this time with stronger microphones. As the dolphins approached clicking noises were heard -- possibly sonar soundings. They gathered into a group in nearby shallow water about 400 feet from the barrier. During this time lots of clicks and squeaky-door sounds were recorded. A scout left the group and examined the barrier. When the dolphin returned he was greeted in the same manner as before. After about four minutes of conversation another scout was sent out. Upon his return he too was greeted with the explosion of whistles. After about two and a half minutes the dolphins merrily clicked through the barrier. Returning into the bay that afternoon, and the next morning leaving the bay, the pod did not send a scout when they came to the barrier.....nor did they even slow down.