Humans differentiate from other animals owing to intelligence and well-developed speech patterns. Most of the primates spend their lives in well-knit complex societies where they need to communicate in order to survive. The communication can happen in form of sound, smell, visual message and even touching. Non-human primates use body language for communication.
Human communication has always been more focused on an oral sound system which involves speech. There is a set meaning behind every word spoken in every man-made language.
THE PRIMATE COMMUNICATION
When it comes to other primates, gestures, odours, facial expressions and vocalisation are used for expressing concerns and psychological state. Many species even use scent marking technique to mark their territories. The scent has always been important, even in human communication.
Human bodies produce pheromones which are powerful chemicals having an effect on other species. Sexual attraction and regulation of ovulation are mainly characterised by the male and female pheromones attracting each other. Scientists believe that it is possible that all the primates might produce such pheromones.
HOW DID SPEECH DEVELOP
Homo sapiens and the origin is speech is a much-contested topic. While other primates use lips and vocal organs for communication, they do not use tongue for modulating the sound. Science is laying focus on deciphering the true origin of language from which the evolution of human speech took place.
Language can only be signed or written whereas it is speech which is the spoken form. Many other animals possess specialised systems for production of sound in order to communicate but none of them uses their tongue for that.
Speech is the modality of language in every culture. The humans control their lips, jaws and even tongue for making a voice. There are various theories that pertain to the origin of speech. Some believe that sounds of language sort themselves out in thoughts in order to come out from the mouth. Gestural theory believes that neural systems control gestural language and vocal language. There are various similarities between other species and humans in this context since even nonhuman primates use gestures to communicate.
There is only a little information available regarding the timing of emergence of language in Homo sapiens. Since speech has left no trace behind (it is spoken and not written), it is very difficult to gauge the correct timing of the evolution of speech.