rm is then amplified by the joint attention of an infant and his caregiver to objects of mutual interest.
The dynamics of intersubjectivity and joint attention are invisible to the untrained eye. What greater joy for parents than playing hide and seek with their baby or seeing their baby show something and then smile? Such a game is necessary to produce the child’s first words around his first birthday.
Hyper-cooperation, intersubjectivity, and joint attention have collectively created a perfect storm for the transition from animal communication to words. Linguists have neglected this transition in favor of the passage from words to grammar, the most famous feature of the language. It is easy to show that the transition from animal communication to words required more structural changes than words to grammar, in particular, the transition from analog primate calls to discrete digital speech. But grammar could not evolve without words.
The analog signals that animals use to communicate vary in intensity and frequency. In addition, the average number of signals used by a given species rarely exceeds two dozen. On the other hand, the variations of meaning in the language are conveyed by the choice of discrete words, the upper limit of which is enormous. A reader of this blog knows more than 50,000.
The shift from the analog emotional signals that animals communicate to discrete words has been a dramatic evolutionary change. Besides the nature of the signal, emotional signals also differ fundamentally from words in that they are involuntary, un-learned, and one-way. Their only function is to influence the behavior of others, such as asserting dominance, demarcating a territory, expressing an interest in mating, alerting others to a predator, finding food, etc.
Emotional signals are also immutable. Dogs can only bark, cats can only purr, birds can only sing, and lions can only roar.
Words are voluntary, learned and arbitrary. Typically, words are also conversational. A speaker and a listener alternate roles while sharing information. Unlike emotional signals, the form of which is fixed, the form of a word is arbitrary. A person can say tree, tree, der baum, el árbol, il arbero, or their equivalent, in over 6,000 spoken languages, or in gestures used in dozens of sign languages.
In sum, the shift from emotional signals from animals to words involved a larger change in form of expression than the shift from words to grammar. These only concern their organization, order, inflection, etc. The shift from animal communication to words marks the first time our ancestors communicated in a conversational, arbitrary fashion. This is not to minimize the importance of the passage from words to grammar but only to clarify that it does not require a new form of expression.
Despite these apparent facts about words, they remain stepchildren in discussions of the evolution of language. As mentioned earlier, the vast literature on the evolution of language has focused on grammar, not words.
Source: Wugapodes / Wikimedia
This imbalance can be attributed to Chomsky and his students. For more than 70 years, they have sought to discover the nature and origins of grammar, possibly at the expense of words. As can be seen from a recent comment, Chomsky seems to be aware of this problem:
The minimal meaning-carrying elements of human languages… are radically different from anything known in animal communication systems. Their origin is entirely obscure, posing a serious problem for the evolution of human cognitive capacities, in particular of language.1
I recognize the importance of understanding grammar and why a theory of grammar would be the ultimate step in explaining the evolution of language. But neglecting the origin of words in the quest to understand the origin of grammar seems to me to put the cart before the horse. It’s like trying to understand molecules without understanding the nature of the elements and the atoms that define them. Just as the efforts of alchemists to transmute lead into gold have hampered our understanding of chemistry,