I agree that the pred language would be complex at times. My comparisons are based on our own language. Growls and roars are primal, very direct. Even a roar can have different meanings as in the big cats such as "don't piss me off", "you pissed me off", "stay away", "MINE", you get the idea. A low growl could mean anything from "Good job, I like what you did" to sexual interest. The enviroment of the situation can even change the meaning of an utterance or gesture. In the human language we will spontaniously utter words or phrases such as "damn", "****", "**** me/you", when in reality we have no intent to do what we say.
Body language / hand signals I would think would be universal. Sharks will arch their back, the hackles of a canine will raise up, ears lay back in both cats and dogs. Some animals, including humans, will cock their head as a response to curosity, puzzlement, indifference, amusement.
The clicks are another part of their language that can be used alone or in conjunction with growls, gurgles and body language. A morse code, if you will. In addition, the Chinese and Japanese written language consist of a large amount of characters, some of them represent an idea or concept as oposed to a word or letter. That makes for a complicated alphabet.
Most do not like my thought on the gutteral whale sounds language. Take note that when a predator first starts to mimic a human phrase, it is very gutteral giving a brief glimpse into its actual speaking voice. In nature, most animals, including man, make their sounds on the lower freqs because it is harder to determine the direction from which the sound comes from ( this has importance in both stealth and self protection ), where as higher pitched sounds are easier to trace to their source ( such as echo location, foghorns, a cry for help).
The more intelligent that a species becomes, the more complex, involved the language becomes. Where the language involved while in a stealthy hunt should be minial; educational, instructorial, and communial language is more involved and used to verbally communicate detailed concepts. EXAMPLE: just in this thread, if we were altogether in person at the same time, how would you translate everything typed into clicks and finger/hand gestures. Point is, an intelligent species has need for a method to explain an idea or method.
Guys, this has been interesting. I enjoied commenting on the subject. It has not been my intention to convert you to my way of thinking. If anything that I have said can be of any use, I am pleased. If not, oh well. Carry on guys
George