Editing Origin of language (section)

=== Lexical-phonological principle ===
Hockett (1966) details a list of features regarded as essential to describing human language.<ref>{{Cite journal |last=Hockett |first=Charles F. |year=1960 |title=The Origin of Speech |url=http://www.gifted.ucalgary.ca/dflynn/files/dflynn/Hockett60.pdf |url-status=dead |journal=Scientific American |volume=203 |issue=3 |pages=88–96 |bibcode=1960SciAm.203c..88H |doi=10.1038/scientificamerican0960-88 |pmid=14402211 |archive-url=https://web.archive.org/web/20140106173517/http://www.gifted.ucalgary.ca/dflynn/files/dflynn/Hockett60.pdf |archive-date=6 January 2014 |access-date=6 January 2014}}</ref> In the domain of the lexical-phonological principle, two features of this list are most important:
* [[Productivity (linguistics)|Productivity]]: users can create and understand completely novel messages.
** New messages are freely coined by blending, analogizing from, or transforming old ones.
** Either new or old elements are freely assigned new semantic loads by circumstances and context. This says that in every language, new idioms constantly come into existence.
* Duality (of Patterning): a large number of meaningful elements are made up of a conveniently small number of independently meaningless yet message-differentiating elements.

The sound system of a language is composed of a finite set of simple phonological items. Under the specific [[phonotactic]] rules of a given language, these items can be recombined and concatenated, giving rise to [[Morphology (linguistics)|morphology]] and the open-ended lexicon. A key feature of language is that a simple, finite set of phonological items gives rise to an infinite lexical system wherein rules determine the form of each item, and meaning is inextricably linked with form. Phonological syntax, then, is a simple combination of pre-existing phonological units. Related to this is another essential feature of human language: lexical syntax, wherein pre-existing units are combined, giving rise to semantically novel or distinct lexical items.{{Citation needed paragraph|date=January 2014}}

Certain elements of the lexical-phonological principle are known to exist outside of humans. While all (or nearly all) have been documented in some form in the natural world, very few coexist within the same species. Bird-song, singing nonhuman apes, and the songs of whales all display phonological syntax, combining units of sound into larger structures apparently devoid of enhanced or novel meaning. Certain other primate species do have simple phonological systems with units referring to entities in the world. However, in contrast to human systems, the units in these primates' systems normally occur in isolation, betraying a lack of lexical syntax. There is new{{When|date=May 2021}} evidence to suggest that [[Campbell's monkey|Campbell's monkeys]] also display lexical syntax, combining two calls (a predator alarm call with a "boom", the combination of which denotes a lessened threat of danger), however it is still unclear whether this is a lexical or a morphological phenomenon.<ref>{{Cite journal |last1=Schlenker |first1=Philippe |last2=Chemla |first2=Emmanuel |last3=Arnold |first3=Kate |last4=Lemasson |first4=Alban |last5=Ouattara |first5=Karim |last6=Keenan |first6=Sumir |last7=Stephan |first7=Claudia |last8=Ryder |first8=Robin |last9=Zuberbühler |first9=Klaus |date=December 2014 |title=Monkey semantics: two 'dialects' of Campbell's monkey alarm calls |journal=Linguistics and Philosophy |volume=37 |issue=6 |pages=439–501 |doi=10.1007/s10988-014-9155-7 |s2cid=3428900}}</ref>