Humans use "language." By language, I mean the thing I am using right now to talk to you.
I know dolphins and orcas have very complex communication systems and also seem to process linguistic and gestural commands.
But do they have their own languages? Where is the evidence for or against? If we take two group of dolphins Group A and Group B, would Group A speak one language and Group B speak another?
Dolphins and orcas do have dialects. Of course there are species specific dialects and it has been shown that orcas reared with bottlenose dolphins tend to learn the latter's dialect. Dolphins of the same species also seem to have regional dialects, as mentioned in this BBC post (I personally do not trust in non-research articles much, but nonetheless in this case the article indicates a certain possibility of a phenomenon). However, this page also reports the same finding and this source seems to be much more reliable. There are citations too that are at present inaccessible to me. Both the sources say that bottlenose dolphins from Shannon estuary in Ireland, "speak" different dialect compared to those from Cardigan Bay in Wales.
The actual research work is this:
Hickey, R. (2005) Comparison of whistle repertoire and characteristics between Cardigan Bay and the Shannon estuary populations of Bottlenose dolphins (Tursiops truncatus) with implications for passive and active survey techniques. School of Biological Sciences, University of Wales, Bangor
Apart from having regional dialects, the cetacean communication also seems to have other features of a "language". I am pasting excerpts from this article which basically reports a study on the acoustic communication or codas in sperm whales. This may apply to dolphins as well.
Individuals within social units have preferred associates among members (Gero et al. 2008), indicating differences in the way an individual interacts with other members of its unit. These preferred associations among unit members suggest the possibility of an individual discrimination system.
.... most adult animals within a social unit shared the most common coda types, with the exception of the mother-calf pair whose repertoires were different from those of other unit members and each other. Apart from the mother-calf differences, the repertoire similarities of other members did not support the hypothesis of individually distinctive coda type repertoires. This sharing of coda repertoires suggests that they allow group membership recognition, at either the unit or clan levels. This hypothesis is further supported by the fact that social units seem to form groups preferentially with other units of their own clan (Rendell & Whitehead 2003b).
To be able to learn human sign language (remember Flipper?), their brains are certainly hard-wired for complex communication.
I once read a paper that showed a whale repeating the same song almost exactly. The song was one and a half hour long. Couldn't find it now, but I found some nice articles showing the complexity, consistency and evolution of whale songs. They also show that different populations have different songs (languages or dialects, if you prefer), and that these songs evolve through the years.
Orcas and dolphins are members of the Odontoceti, while whales are Mysticeti. I don't know if the verbal communication of the first group is as elaborated as that of the second, but I don't discard this hypothesis.
Whale Song Explained - great work of art using colored symbols to illustrate the different patterns of sound that make up whale songs.
Large Scale Changes over 19 Years in Songs of Humpback Whales in Bermuda
Dynamic Horizontal Cultural Transmission of Humpback Whale Song at the Ocean Basin Scale
