Language: Universals, Principles and Origins
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Language: universals, principles and origins. Ramon Ferrer i Cancho Barcelona, 2003. Laboratori de Sistemes Complexos (GRIB−UPF) & Universitat Politecnica de Catalunya Resum En aquesta tesi s'investiguen vells i nous universals ling¨u´ıstics, ´esa dir, propietats que obeeixen totes les lleng¨uesde la Terra. Tamb´es'estudien prin- cipis b`asicsdel llenguatge que prediuen universals ling¨u´ıstics. En concret, dos principis referencials, m´ınim esfor¸cde codificaci´oi m´ınim esfor¸cde decodifi- caci´o,una reformulaci´odels principi de m´ınimesfor¸cde G. K. Zipf pel qui parla i pel qui escolta. Els esmentats principis referencials prediuen la llei de Zipf, un universal de la freq¨u`enciade les paraules en el punt de m`aximatensi´oentre necessitats de codificaci´oi decodificaci´o.Encara que s'han proposat processos trivials per explicar la llei de Zipf en contextos no ling¨u´ıstics,aqu´ıes recolza la signific`anciad'aquesta llei per al llenguatge hum`a. Minimitzar la dist`ancia eucl´ıdeaentre paraules sint`acticament relacionades dins frases ´esun principi que prediu projectivitat, un universal que afirma que els arcs entre paraules sint`acticament relacionades dins una frase no es creuen en general. D'una altra banda, aquesta minimitzaci´ode la distancia f´ısicaprediu (a) una distribuci´o exponencial per a la distribuci´ode la dist`anciaentre paraules sint`acticament relacionades (b) superioritat de l'ordre SVO en l'´usreal de les lleng¨uesdel m´on. Aqu´ı es presenten propietats totalment noves de les xarxes de depend`encies sint`actiques,´esa dir, distribucions de grau potencials, fenomen del m´onpetit, assortative mixing i organitzaci´ojer`arquica.Enlloc d'una gram`aticauniversal, es proposa una ´unicaclasse d'universalitat per a les lleng¨uesdel m´on.Sintaxi i refer`enciasimb`olicas´onunificades sota una ´unicapropietat topol`ogica:connec- tivitat en la xarxa d'associacions senyal-objecte d'un sistema de comunicaci´o. Assumint la llei de Zipf, no sols se segueix connectivitat sin´oles propietats de xarxes sint`actiquesreals esmentades m´esamunt. Per tant, (a) els principis ref- erencials s´onels principis de la sintaxi i la refer`enciasimb`olica,(b) la sintaxi ´esel subproducte de principis simples de la comunicaci´oi (c) les propietats es- mentades de les xarxes de depend`enciessint`actiqueshan de ser universals si la llei de Zipf ´esuniversal, que ´es el cas. Es mostra que la transici´oa llenguatge ´esdel tipus de les transicions de fase cont´ınues en f´ısica.Per tant, la transici´oa llenguatge no va poder ser gradual. Es presenta el morfoespai redu¨ıtque resulta d'una combinaci´od'un principi de minimitzaci´ode la dist`ancia i un principi de minimitzaci´ode la densitat de connexions com una hip`otesi alternativa i una perspectiva prometedora per a xarxes ling¨u´ıstiquesque pateixin pressions per comunicaci´or`apida.La present tesi ´es´unicaentre les teories sobre els or´ıgens del llenguatge, en el sentit que (a) explica com les paraules o els senyals es combinen de forma natural per tal de formar missatges complexos, (b) valida les seves prediccions amb dades reals, (c) unifica sintaxi i refer`enciasimb`olica i usa ingredients que ja estan presents en els sistemes de comunicaci´oanimal, d'una forma que cap altra aproximaci´ofa. El marc presentat ´esun canvi radi- cal en la recerca dels universals del llenguatge i els seus or´ıgensa trav´esde la f´ısicadels fen`omenscr´ıtics.Els principis presentats aqu´ıno s´onels principis del llenguatge hum`a,sin´oels principis de la comunicaci´ocomplexa. Per tant, els propdits principis suggereixen noves perspectives per a altres sistemes naturals de transmissi´od’informaci´ocomplexa. Abstract Here, old and new linguistic universals, i.e. properties obeyed by all lan- guages on Earth are investigated. Basic principles of language predicting linguis- tic universals are also investigated. More precisely, two principles of reference, i.e. coding least effort and decoding least effort, a reformulation of G. K. Zipf's speaker and hearer least effort principles. Such referential principles predict Zipf's law, a universal of word frequencies, at the maximum tension between coding and decoding needs. Although trivial processes have been proposed for explaining Zipf's law in non-linguistic contexts, Zipf's law meaningfulness for human language is supported here. Minimizing the Euclidean distance between syntactically related words in sentences is a principle predicting projectivity, a universal stating that arcs between syntactically linked words in sentences generally do not cross. Besides, such a physical distance minimization success- fully predicts (a) an exponential distribution for the distribution of the distance between syntactically related words and (b) subject-verb-object (SVO) order superiority in the actual use of world languages. Previously unreported non- trivial features of real syntactic dependency networks are presented here, i.e. scale-free degree distributions, small-world phenomenon, disassortative mixing and hierarchical organization. Instead of a universal grammar, a single univer- sality class is proposed for world languages. Syntax and symbolic reference are unified under a single topological property, ie. connectedness in the network of signal-object associations of a communication system. Assuming Zipf's law, not only connectedness follows, but the above properties of real syntactic networks. Therefore, (a) referential principles are the principles of syntax and symbolic reference, (b) syntax is a by product of simple communication principles and (c) the above properties of syntactic dependency networks must be universal if Zipf's law is universal, which is the case. The transition to language is shown to be of the kind of a continuous phase transition in physics. Thereafter, the tran- sition to human language could not have been gradual. The reduced network morphospace resulting from a combination of a network distance minimization principle and link density minimization principle is presented as an alternative hypothesis and a promising prospect for linguistic networks subject to fast com- munication pressures. The present thesis is unique among theories about the origins of language, in the sense that (a) it explains how words or signals nat- urally glue in order to form complex messages, (b) it validates its predictions with real data, (c) unifies syntax and symbolic reference and (d) uses ingredi- ents already present in the animal communication systems, in a way no other approximations do. The framework presented is radical shift in the research of linguistic universals and its origins through the physics of critical phenomena. The principles presented here are not principles of human language, but prin- ciples of complex communication. Therefore, the such principles suggest new prospects for other information transmission systems in nature. Language: universals, principles and origins. Ramon Ferrer i Cancho email: [email protected] Complex Systems Lab (GRIB-UPF) and Universitat Polit`ecnica de Catalunya. i Final version ii Departament de Llenguatges i Sistemes Inform`atics Universitat Polit`ecnica de Catalunya Llenguatge: universals, principis i or´ıgens. Programa d’intel.lig`encia artificial. Intensificaci´ode llenguatge. Tutor de tesi Director de tesi Dr. Horacio Rodr´ıguez Dr. Ricard V. Sol´e Hontoria Laboratori de sistemes Departament de Llenguatges i complexos sistemes inform´atics Grup de recerca en inform`atica Universitat Polit`ecnica de biom`edica (GRIB) Catalunya (UPC) Universitat Pompeu Fabra (UPF) Acknowledgements It is not easy to find words for expressing my great indebtedness to Ricard Sol´e. He taught me to think as a scientist. His teachings, projects and discussions about complex systems theory are behind the present inquiry. Many of the things he has taught me are beyond beyond the scope of science. He supported the crazy idea of a thesis about language when quantitative approaches are the issue of minority of researchers mostly in Central-East Europe and linguistics is dominated by purely axiomatico-deductive phylosophical approaches. The Complex Systems Lab (and the old Complex Systems Research Group) has been a privileged scientific environment. Many members have been my teachers, scientific therapists, reviewers and friends: David Alonso, Javier G.P. Gamarra, Pau Fern´andez, Jos´eMar´ıaMontoya, Romualdo Pastor, Jordi Del- gado, Susanna Manrubia and Bartolo Luque. Pau’s technical assistance deserves special mention. I based Appendix B on an unpublished manuscript by Susanna Manrubia. Outlines of proofs and the underlying complete proofs in Chapter 7 are entirely due to B´ela Bollob´as and Oliver Riordan. Both have provided very hepful comments concerning other chapters. I thank Ludmila Uhl´ıˇrov´aand Jan Kr´al´ık for the opportunity to analyze the Czech corpus and the Dependency Grammar Annotator Project for their publicly available small Romanian corpus. I would like to thank Toni Hern´andez for his deep and sharp reading of the present work. I am very grateful to the Santa Fe Institute and the Institute for Advanced Study (IAS) for his hospitality and stimulating environment. I want to thank Martin Nowak at the IAS and Reinhard Ko¨ehler at Trier Universit¨at for hospitality, supporting my research and helpful discussions. Reinhard Ko¨ehler’s synergetic understanding of language and independence with respected to main- stream theoretical linguistics have been of great value. I thank B´ela Bollob´as and Oliver Riordan for shedding light on the combinatorics of language. I will try to list the remaining people whose support, comments or criti- cisms have influenced the present work (forgive me those I may have forgotten), i.e. Andrei G. Bashkirov, Dereck Bickerton, John Buck, Rafael Cases, Faust Di´eguez, Josep D´ıez,Thomas Giv´on, Peter Harremo¨es, Dick Hudson, Natalia Komarova, David Krakauer, Alun Lloyd, Brenda McCowan, Francesc Mart´ın, Alexander Mehler, Igor Melcˇuk, George Miller, Partha Niyogi, Joshua Plotkin, Francesc Reina, Duane Rumbaugh, Ton Sales, Ryuji Suzuki, Jared Taglialatela, Flemming Topsøe, Enric Vallduv´ıand Sandra L. Vehrencamp.