A fundamental problem of language origin is the Continuity Paradox: language acquisition apparently only occurs in situations involving pre-existing languages, or at the very least pidgin communication. In the 19th century, philosophers and linguists proposed a number of hypotheses to explain the origin of language, which are noteworthy for their names even if none of them have vanquished their competitors in the battles for scientific credibility. The first such names were coined by Otto Jespersen as a way of deriding the hypotheses as simplistic speculation. Once the names caught on, new hypotheses that have arisen often have been given names with a similar style. It seems unlikely that one hypothesis describes the whole process; more likely, multiple mechanisms described by multiple hypotheses, working together or one after another, contributed to the development of language.
This hypothesis places the origin of human language in onomatopoeia: the various imitative sounds that humans make to mimic the sounds of the world around them. For example in English, boom is the sound of thunder, oink is the sound made by a pig, and tweet is the sound made by a small bird. Of course, many languages contain their own onomatopoeic words (eg. in Basque, ai-ai, which means "ouch-ouch", refers to a knife).
There are several reasons why this hypothesis has not met with universal acceptance, as it does not adequately explain the creation of words for inanimate objects, such as rocks, much less prepositions and other grammatical particles or abstract concepts. Words marked by onomatopoeia are conspicuous and somewhat unusual in most languages. The "ding-dong" hypothesis is therefore not considered to be a complete explanation for the origin of language.
Similar to the "ding-dong" hypothesis, this one has humans forming their first words by imitating animal sounds.
Not only do all of the objections involving other sorts of onomatopoeia explanations apply here, it is worthy to note that the names of animal sounds are strongly culturally determined and differ remarkably from one culture to the next, as the article on oink sets forth. It seems difficult to accept that humans learned to speak to one another by talking to the animals.
According to this hypothesis, the first words developed from sighs of pleasure, moans of pain, and other semi-involuntary cries or exclamations. These vocalisms then became the names of the phenomena that made people say them.
Most of the objections to the "ding-dong" hypothesis apply here also. Such words are found in most languages; they are conspicuous by their preverbal nature and incomplete assimilation into the lexicon. Moreover, they are culturally determined, and themselves show a great deal of arbitrariness.
Charles Darwin lent his authority to this hypothesis. According to this, human language represents the use of oral gestures that began in imitation of hand gestures that were already in use for communication. Vilayanur S. Ramachandran's research into synesthesia and sound symbolism would seem to support this hypothesis.
The difficulty with this hypothesis, is that it begs the question: it requires that a fairly sophisticated repertoire of gestures be in place already for humans to imitate with their mouth gestures. It assumes the existence of a language of gestures without explaining how it arose (however, see Nicaraguan Sign Language). At any rate, though sign languages do have somewhat imitative (or iconic) gestures, they also contain quite arbitrary symbols and have vastly different meanings in different human cultures.
One other difficulty with this hypothesis is that hand gestures and facial expressions are useless unless they are seen. That means it must either be daylight, or firelight, and with nothing blocking one's view. For facial expressions, the communicators must also be facing each other. In addition, hand gestures are difficult if the hands are doing something else.
According to this hypothesis, human language begins with the use of arbitrary symbols that represent warnings to other members of the human band. It is agreed that one sort of vocal cry means that lions have been spotted in the area, and another one indicates a snake. You holler one thing at your neighbour to warn them, "Don't eat that! It'll make you sick!" and something distinguishable to warn them "Don't eat that! It's mine!"
This hypothesis seems to have the potential to explain the perceived diversity of human speech; obviously the warning cries uttered here are to some measure arbitrary. It is less certain that this hypothesis could explain how more abstract features of human language developed.
According to this hypothesis, language arose in rhythmic chants and vocalisms uttered by people engaged in communal labour.
This may have more to do with the origins of poetry than with language itself. Sea chanteys, jody calls, and similar work songs all show humans engaged in communal work improvising with their language around the rhythms of their work. It is uncertain from this hypothesis how meanings came to be associated with the vocalisms uttered by the workers.
* Watch the Birdie
This one is associated with ethologist and linguist E. H. Sturtevant. According to this hypothesis, human language became elaborated because humans found selective advantage in being able to deceive other humans. Since exclamations and vocalisms can involuntarily reveal your true mental state, humans learned to feign them in order to deceive others for selfish advantage.
* The Psychedelic Glossolalia Hypothesis
This theory states that speech was inspired by psychoactive fungi. The line of reasoning is thus: A common symptom of tryptamine intoxication is glossolalia, more commonly known as “speaking in tongues”. As the continent of Africa began to dry, grassland savannas opened, forcing humans out of the forests and into the plains where the dung of large herbivores was ubiquitous. Species of tryptamine-bearing fungi like Psilocybe, which live on animal dung, would have been very attractive to human populations seeking a new food source. Regular ingestion of the fungi could, over a long time, have stimulated complex vocalizations that eventually led to communicative speech.
* Non-naturalistic hypotheses of the origin of language
Some people resort to traditional narratives, myths, or legendary history in order to explain the origin of human language.