Cours de Ted Briscoe =?iso-8859-1?Q?=E0_?=l'ENS Ulm en mars (Evolutionary linguistics)

[Thierry Poibeau]

Chers collègues,

Le laboratoire Lattice (http://www.lattice.cnrs.fr/), avec le soutien du labex Transfers (http://transfers.ens.fr/), accueille Ted Briscoe (http://www.cl.cam.ac.uk/~ejb1/), de l’Université de Cambridge, pour une série de cours qui seront donnés en mars à l’Ecole normale supérieure (45 rue d’Ulm), sur le thème de la « modélisation de l’évolution des langues » (« evolutionary linguistics »).

Les cours auront lieu aux dates et lieux suivants :

	• mardi 11 mars, de 10h30 à 12h30 : salle Celan
	• jeudi 13 mars, de 10h30 à 12h30 : salle R
	• mardi 18 mars, de 10h30 à 12h30 : salle IHMC
	• jeudi 20 mars, de 10h30 à 12h30 : salle R

Le programme est détaillé ci-dessous et à l’adresse suivante : http://transfers.ens.fr/index.php/activites/professeurs-invites/495

Tout le monde est le bienvenu, dans la imite des places disponibles. 

Bien cordialement,

Thierry Poibeau

----


Topics in Evolutionary Linguistics 
Ted Briscoe
University of Cambridge

Introduction

Until recently the word "natural" in natural lan­guage has served only to dis­tin­guish the study of human lan­guages from that of logics or pro­gramming lan­guages. Moreover, the dis­tinction has been metho­do­lo­gi­cally without much content since gene­rative lin­guistics treats human lan­guage as a static well-​​formed stringset and employs the same formal tools — formal lan­guage theory, deno­ta­tional semantics — as theo­re­tical com­puter science. Many theo­re­tical lin­guists would pro­bably agree, at least metho­do­lo­gi­cally, with Richard Montague’s famous dictum, "I reject the contention that an important theo­re­tical dif­fe­rence exists between formal and natural lan­guages" (Mon­tague), because not to would appear to pre­clude the pos­si­bility of formal lin­guistics. One direct conse­quence has been that the study of lan­guage change and variation has remained mostly des­criptive and largely outside the realm of at least gene­rative lin­guistics. Inevi­tably, the focus of research has been on the indi­vidual speaker and her idiolect.

Recent acc­counts of lin­guistic change, learning and typology (e.g. Hurford, Niyogi, Kirby, Steels, Croft, Deut­scher, etc.) model lan­guage as a dynamic system (variation + inhe­ri­tance through learning), in some cases with adap­tation (lin­guistic selection amongst variants). The crucial shift in pers­pective in these models is to study (popu­la­tions of) (gene­rative) lan­guage learners and users, as opposed to focussing on the indi­vidual speaker and her idiolect at one point in time. The conclusion that lan­guage is a dynamic system is a direct and inevi­table conse­quence of this shift of pers­pective. One which can be seen as an extension rather than rejection of the insights and achie­ve­ments of gene­rative lin­guistics. The study of lan­guage as a dynamic system will require a very dif­ferent research paradigm based largely on com­pu­ta­tional simu­lation (as mathe­ma­tical ana­lysis has so far been res­tricted to extremely simple and arti­ficial dynamic systems). Never­theless, there is a rich body of theo­re­tical work on which to draw, both in evo­lu­tionary biology and in the study of naturally-​​occurring complex dynamic systems.

Dynamic systems, such as the weather, can be rule-​​governed (deter­mi­nistic), complex in the sense of unpre­dic­table (chaotic), but not adaptive. Others, such as the immune system, are adaptive and complex. Com­plexity in dynamic systems can arise through constraints on variation (self-​​organisation) as much as through (com­peting) selection pres­sures. Constraints on lan­guage variation will be a conse­quence of the capa­cities and limi­ta­tions of the lan­guage users in whom the lin­guistic system is embedded — just as the constraints of che­mistry places limi­ta­tions on variation in bio­lo­gical orga­nisms. As lan­guage users are also subject to evo­lution, and pres­sures for greater lear­na­bility, expres­sivity and inter­pre­ta­bility are often in conflict, so (co-​​evolutionary) inter­ac­tions are likely, contri­buting both to the com­plexity of the phe­nomena and their study (Laland and Brown, 2011:Ch7). The use of evo­lu­tionary ter­mi­nology in (dia­chronic) lin­guistics is not new (see e.g. McMahon, 1994:Ch12) but, advances in the unders­tanding of dynamic systems and the avai­la­bility of com­pu­ta­tional simu­lation tech­niques now make it pos­sible to move beyond the use of evo­lution, pri­marily as metaphor, and study lan­guage directly from an evo­lu­tionary perspective.

The lectures will describe a computational simulation model which characterises languages as complex adaptive systems selected for learnability, interpretability and/or expressivity within a population of language using agents (Briscoe, 2000). This characterisation is a direct consequence of shifting the study of language from synchronic idiolects to evolving populations of classical generative agents learning, producing and interpreting language in a shared arena. As each new generation of learners acquires a grammar from the utterances in the arena of use to which they are exposed, they, in effect, select from this arena the more learnable variants (Hurford, 2012). Or, to turn this on its head, variant language constructions compete for learners, and the more learnable ones tended to be selected more often. However, learnability is counter-balanced by expressivity (e.g. economy of production), interpretability (e.g. working memory limitations and parsability), as well as "extraneous" factors such as population movement and social power or prestige which undoubtedly
play a role, leading to competing linguistic selection pressures (competing motivations in diachronic linguistics) and thus a
correspondingly dynamic and complex adaptive landscape.

Topics

Each presentation will last about 40 minutes leaving 20 minutes for
questions and general discussion. I'll suggest some further reading on
each topic after each session and make my slides available to all
participants after the sessions.

1) Introduction -- The Model
  a) Generative Linguistics
  b) Universal Darwinism
  c) Linguistic Units of Selection
  d) Linguistic Universals / Tendencies
  e) Gene-Language Co-evolution
  f) Language Agents

2) First Language Acquisition
  a) Desiderata for a Model of FLA
  b) Generalized Categorial Grammar
  c) (Evolutionary) Bayesian Learning
  d) Iterated Learning Models
  e) Priors and fixed points?

3) Syntactic Change and Typology
 a) (Statistical) Universals
 b) Working Memory and Parsability
 c) S-curves and Power Laws
 d) Populations of Language (Learning) Agents
 e) Uniform Information Density
 f) Language Contact and Social Factors

4) Co-evolution of Language and Genes
 a) Genetic Assimilation / Baldwin Effect
 b) Populations of Evolving Language Agents
 c) Learning Bias vs. Linguistic Bias?
 d) Learning Costs and (De)Correlation
 e) Timescales in Language Evolution

5) Grammar vs. Inference
 a) Relative Clause Formation Strategies
 b) Ambiguity and Dependency Length
 c) Trade-offs between (en/de)coding and inference
 d) Ambiguity and Prosody
 e) Relative Clause Usage

6) Second Language Acquisition
 a) Differences FLA and SLA?
 b) Morphology vs. Syntax in Diachrony
 c) Perceptual Factors in F/SLA
 d) Directionality in Language Change?
 e) (Un)Folding of Languages

7) More Putative Linguistic Universals
 a) Universal Grammar vs. Selection Pressures
 b) Nested, Cross-serial or Intersecting Dependencies
 c) Head (Dis)Harmony and Dependency Length
 d) The Final-over-Final Constraint
 e) Convergent Evolution -- Functional vs. Arbitrary?

8) Conclusions, Issues, and Future Work
 a) Comparison with Other Approaches
 b) Methodology for Evolutionary Linguistics
 c) Desiderata for Simulation Models
 d) Maths vs. Computation
 e) Sociolinguistic Networks of Interaction

Background Reading

Briscoe, E.J. 
    Evolutionary Prerspectives on Diachronic Syntax
    In Pintzuk S. et al, eds., 
    Diachronic Syntax: Models and Mechanisms
    Oxford University Press, 2000
    http://www.cl.cam.ac.uk/users/ejb1/digs-paper.pdf

Croft, W.
    Explaining Language Change
    Longman
    2000

Deutscher, G.
    The Unfolding of Language
    Heinemann
    2005

Hawkins, J.A. 
    A Performance Theory of Order and Constituency 
    Cambridge University Press, Cambridge 
    1994 

Hurford, J. 
    The Origins of Grammar
    Oxford University Press
    2012

Kirby, S. 
   Function, Selection and Innateness
   Oxford University Press
   1997

Laland, K and Brown, G.
   Sense and Nonsense: Evolutionary Perspectives on Human Behaviour
   Oxford University Press
   2011

McMahon, A.
  Understanding Language Change
  Cambridge University Press
  1994

Niyogi, P. 
  The Computational Nature of Language Learning and Evolution
  MIT Press
  2006

Steels, L.
  Language is a Complex Adaptive System
  6th Int. Conf. on Parallel Problem Solving
  Springer
  2000
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