Date: 08-Feb-2007
From: Michael Arbib <arbibusc.edu>
Subject: How New Languages Emerge
Announced at http://linguistlist.org/issues/17/17-1250.html
AUTHOR: Lightfoot, DavidTITLE: How New Languages EmergePUBLISHER: Cambridge University PressYEAR: 2006
Michael A. Arbib, Computer Science, Neuroscience and USC Brain Project,University of Southern California
David Lightfoot develops his thesis that new languages emerge becausechildren internalize new grammars from the flux of language use aroundthem. To do this, he offers two complementary accounts: one of languageacquisition, and the other of language change. Lightfoot has aimed the bookat the general reader, but perhaps a quarter of the material will be hardgoing for readers not used to reading standard linguistic examples. Somefootnotes announce that certain portions of the book are recycled from 2earlier volumes, ''How to set parameters: arguments from language change''(1991) and ''The development of Language Acquisition'' (1999). I have notgone back to make an explicit comparison with these volumes but thesefootnotes did alert me to ask ''How much of this book reflects post-1990scholarship?'' The answer seems to be that Lightfoot has kept abreast of theliterature on historical linguistics on the history of English and relatedstudies of Scandinavian, but has followed almost no literature on otherthan the Romance and Germanic languages, save for Nicaraguan Sign Language.Given that Lightfoot asserts that the new historical linguistics isexcitingly interdisciplinary, it is even more striking that his discussionof language acquisition is devoid of almost any analysis of actual studiesof children acquiring language.
EVALUATION
Lightfoot reviews the valuable distinction between E-language andI-language -- between the wild variety of utterances ''out there'' and theknowledge of language inside the head of the individual speaker. The childjoins the language community by constructing an I-language thatapproximates aspects of the ambient E-language. The key point for thediscussion of language change is that the E-language is sufficientlyheterogeneous and the child's sample sufficiently small that differentchildren may end up with different I-languages. As old speakers die and newspeakers arise, the set of I-languages of the community changes. Theircombined effect may preserve the E-language of the previous generation,change it in minor ways, or start changes that may cumulatively yield a newE-dialect or E-language. I agree with this general framework but it leavesopen (at least) two major questions:
Language Acquisition: What is the nature of an I-language and how is itacquired by the individual? A sub-question is how much of the I-language isacquired by the young child, and how much may an individual's I-languagechange over the lifespan?Language Change: Language may change because of innovations invented anddisseminated by young and older adults, or it may occur because younglanguage learners extract new patterns from the ambient fluctuations ofE-language to create a new population of I-languages. Is this an either/orsituation, or are both processes operative?
LANGUAGE ACQUISITION
On p.7, Lightfoot states that ''children are internally endowed with certaininformation, what linguists call Universal Grammar (UG), and, when exposedto primary linguistic data, they develop a grammar, a mature linguisticcapacity, a person's internal language or I-language. The essentialproperties of the eventual system are prescribed internally and are presentfrom birth''. There is no mention here or elsewhere in the book that manylinguists disagree with this, and thus there is no occasion to reviewactual child development data to test alternative hypotheses. Consider, forexample, the work of Jane Hill (reviewed by Arbib & Hill, 1984) on languageacquisition. Jane modeled data she had gathered from a 2-year old child bya process in which the child interiorizes fragments of what it hears tobuild what we would now call constructions, based on the child's currentconcerns and interests. Over time some constructions merge with others,some fall into disuse, some gain complexity, and the lexicon grows and iscategorized in tandem with the development of these constructions. Suchideas are now well developed in the recent volume by Tomasello (2003). Theissue here is not which approach to language acquisition is correct but,rather, the need for evaluation of alternative theories, addressing therelated data on children's development.
Implicitly, the phrase ''a grammar, a mature linguistic capacity, a person'sinternal language or I-language'' seems to omit the person's lexicon fromthe I-language, and Lightfoot explicitly excludes social conventions oflanguage use from the I-language. He seems to consider the grammar as a setof abstract rules of syntax and phonology, though the latter receiveslittle consideration here.
Anyway, the first major unquestioned hypothesis of the book is what I willrefer to as the UG/LAD hypothesis – that there is an innate UG and that thechild acquires its I-language (i.e., its syntax) via a Language AcquisitionDevice (LAD) which scans the ambient E-language to determine which settingsof the parameters of UG match the sentences the child hears. Lightfootoffers the usual Poverty of the Stimulus argument but fails to note thatrecent literature militates against this argument (e.g., Pullum & Scholz,2002). Indeed, when Lightfoot provides a critique of one approach toinstantiating UG/LAD, his strategy -- while offered as a better approach toUG/LAD -- may actually be more in keeping with approaches that dismissUG/LAD. Lightfoot argues convincingly that one approach to the UG/LADhypothesis -- setting parameters by scanning through the entire E-language(Clark, 1992; Gibson & Wexler, 1994) -- must fail. The argument is based onthe logic of a combinatorial explosion, not an analysis of developmentaldata. He then argues -- again, I think, convincingly -- that the child doesnot attend to the full complexity of adult sentences but instead attends tofragments. I also agree that the child will not process complex sentences(at least at first -- Lightfoot is not explicit about the ''maturationschedule'') but will focus on simple sentences in the search for structure.Where Lightfoot and I differ is that he sees the process of ''scanningfragments'' as a search for ''cues'', which are items from UG which canstructure the sentence fragments. The catch is that these cues are highlytheory-laden. For example, the child is asked to recognize an empty verbslot, or recognize a V-DP structure. However, no account is given of howthe young child recognizes an empty slot, or knows a DP when he sees one.In what way, then, do I see Lightfoot as suggesting how the problem of thepoverty of the stimulus might be addressed without recourse to UG/LAD? Itis because once one accepts that the child is not looking at the entireE-language to switch in a complete grammar from those licensed by UG, butinstead is slowly building up a repertoire of ''generation strategies'' forfragments of a simplified subset of the E-language, then the way is open totest the hypothesis that an innate UG is unnecessary after all. Instead onemay posit that the child builds up a set constructions that graduallyextend its ability to use language both to get others to minister to itsneeds and to engage in a broadening range of social interactions.
Lightfoot pays essentially no attention to data on language acquisitionsave to note the 4 stages that Clahsen & Smolka (1986) describe in theacquisition of German. No theory is offered of how the child activates''cues'' from the observed E-language nor -- perhaps the most crucial point-- how the child avoids activating cues that seem to match other parts ofthe language input. The reader seriously concerned with understandinglanguage acquisition will find little of value in Lightfoot beyond the ideathat early acquisition is driven by attending to fragments of simplesentences rather than matching parameters against a wider sample thatincludes complex sentences.
The reader wishing to understand the state of the art in the UG/LADapproach to first language acquisition and the subtleties that arise whenone then considers language acquisition should turn to Dalila Ayoun's(2003) ''Parameter Setting in Language Acquisition''. Ayoun makes clear thatmany problems bedevil this work. The most fundamental problem is that thereis no agreement on which principles and parameters (or cues) form UG, orwhen two putatively innate features of language are governed by a singleparameter. Another problem is to what extent the parameters or cues must beactivated according to a maturation schedule, rather than as and when asentence is encountered with the appropriate structure. And then the issueof second language acquisition raises all sorts of problems about whether achild's brain can hold 2 settings of the same parameter and bind them touse of the appropriate language. The reader may either find this a superbreference for further work on the UG/LAD approach or (as I did, presumablycontrary to Ayoun's intentions) a strong indication that UG/LAD does notsolve the language acquisition problem. In either case, it is a valuable book.
As Ayoun acknowledges and Lightfoot does not, the key to work on languageacquisition is to analyze data on how children acquire language. Here auseful compendium is Eve Clark's (2003) ''First Language Acquisition''.Unlike Lightfoot's view of I-language as being restricted to syntax andphonology, Clark integrates social and cognitive approaches to how thechildren understands and produces sounds, words and sentences -- all withinthe context of learning to use language to cooperate and achieve goals.
LANGUAGE CHANGE
Lightfoot's Chapter 2, ''Traditional Language Change'', which ''draws heavilyon chapter 2 of Lightfoot (1999)'', introduces the study of historicallinguistics by presenting two lines of study that culminated in thenineteenth century -- the study of the Great Vowel Shift and relatedaspects of sound change, and the charting of ''family tress'' for theIndo-European languages. He emphasizes that this research, for all itssuccess, has shortcomings because the researchers lacked the criticaldistinction between E-language and I-language.
After introducing UG/LAD and his views on language acquisition, Lightfootthen develops his child-centered theory of historical language change inChapters 5 and 6, ''New E-languages cuing new I-languages'' and ''The use andvariation of grammars.'' I earlier raised the question of whether languageschange because of innovations invented and disseminated by adults, orbecause of the way young language learners extract new patterns from ofE-language or both. Lightfoot again has no time to mention or debatealternative hypotheses: He insists without question that children'sformation of new I-languages is the key to how languages change. There isno discussion of alternative views and thus no marshaling of support for''his'' view. However, Croft (2000) offers a very different view of languagechange and even devotes Section 3.2 to a critique of ''The child-basedtheory of language change'', including an explicit analysis of some ofLightfoot's earlier work. Lightfoot does not mention this.Lightfoot offers what I (as an outsider) feel to be an excellent summary ofmaterial from the history of English (and some related material on changesin Scandinavian language) but offers no related data on child language. Hismethod is to simply observe that a change occurs in the texts from date xto date y and then state without evidence that change in children'sI-languages must have been the driving factor. However, he usually statesthat changes in E-language (e.g., due to Viking invasions) must havetriggered the changes. He offers no evidence (but see below) that thechanges were not made first by adults accommodating to the novel languageflux, and that children's language acquisition played a secondary role. Totake a contemporary example: the rapid changes in cell phone technology aredriven in great part by the enthusiasm of teenagers for new devices andservices, but the new devices and services are usually created bythirty-year-olds (more or less) with the consumers providing selectivepressure. In the same way, it seems to me strange to privilege the languagelearning of infants over the effects of adult innovation in response to awhole host of historical processes including language contact.
Let's consider one example (p.131-2): ''Bean (1983) examined nine sectionsof the Anglo-Saxon Chronicle [and] counted four constructions that neededto be analyzed with the verb remaining in its VP. She found 50% of suchverbs in the section [sic] until 755, 25% in 865-864, ..., [and] 22% in1132-1140. ... The option of moving the verb to a higher position wasexercised increasingly over a period of several hundred years. This no morereflects a change in grammars than if some speaker were shown to use agreater number of passive and imperative sentences. ... Nonetheless ...changes in E-language, representing changes in the use of grammars, if theyshow a slight cumulative effect, might have the consequence of changing therobustness of the expression of cues, leading to new grammars. This seemsto be what happened during Middle English.'' And that's the method -- gatherdata showing historical change, then argue that I-languages might change asa result, and then assert without discussion that the change in I-languagesexplains the E-language change. In my opinion, Lightfoot could make abetter case for the importance of child language in language change if heabandoned the UG/LAD theory that an I-language is just a new combination ofinnate parameters or cues. A construction-based view would not only supportthe emergence of true novelty, but would also allow the child to acquiremultiple constructions even though the generative grammarian might assignthem to different UG parameter settings and then have as part of herI-language the ''probability settings'' for when to apply the constructionsin different settings (cf. Eve Clark's usage-based approach). One couldthen see the changes analyzed by Bean (1983) as marking a continuous changein I-languages.
Perhaps the most promising Chapter, Chapter 7 on ''The eruption of newgrammars'', discusses creoles and signed languages but, beyond discussingthe latest paper (Senghas et al., 2004) on Nicaraguan Sign Language showslittle sign of reworking beyond Lightfoot's earlier books (1991, 1999). Thediscussion of creoles usefully stresses the interaction of substrate andsuperstrate languages in the formation of a creole, as against a BioprogramHypothesis or expression of ''unmarked'' parameters in UG. However, Lightfootagain emphasizes the children's formation of I-languages without analyzingwhat adult interactions formed the pidgin from which the creole emerged, orciting historical studies of the circumstances under which the substrate orsuperstrate language may more heavily influence the final grammar (see.e.g., Holm 2000 for a review of relevant material). Nicaraguan SignLanguage is, of course, fascinating because the children who created thelanguage over the course of some 30 years had no extant sign languages tocreolize. One may thus conclude that the children's formation ofI-languages was crucial, with the I-languages of each cohort providing theE-language for the innovations of the next cohort. Lightfoot also usefullycites data showing ways in which a child exposed to ''broken'' samples ofE-language may end up with an I-language that allows him to produce abetter version of the E-language than his models could provide. However,there is nothing here that proves that all children have an innate UG/LADfor signed as well as spoken language, and that Nicaraguan Sign Languagewas created by children accumulating enough E-language to allow the youngerchildren to set parameters (or cues) for which there was hitherto noevidence. Indeed, Senghas (2003) found that changes in the grammar ofNicaraguan Sign Language first appear among preadolescent signers, soonspreading to subsequent, younger learners, but not to adults. I would thussay that older children sought to find new ways to communicate; and thatwhen they succeeded the new pattern of signing caught on with others and soformed the E-language, with formation of I-languages playing a secondaryrole of partial regularization. Again, the problem with Lightfoot's book isthat he never spells out the alternatives, and thus never marshals the dataneeded to support his hypotheses.
And so we come to the concluding chapter, ''A new historical linguistics''.We saw that Chapter 2 introduced the nineteenth century study of the GreatVowel Shift and the charting of ''family trees'' for the Indo-Europeanlanguages, and emphasized that the research has shortcomings because theresearchers lacked the critical distinction between E-language andI-language. One might hope then that the book would finish on a triumphalnote, celebrating the new insights that have accrued from using the UG/LADhypothesis to ground a child-centered theory of historical language change.Instead we find that the book is silent on how to move forward the study ofhistorical phonology. As for getting insight into the historicalrelatedness of languages, Lightfoot only offers a counsel of despair(p.173): ''It is impossible to know what a corresponding form could be insyntax, hard to know how one could define a sentence of French thatcorresponds to some sentence of English [sic] and hard to see how thecomparative method could have anything to work with.'' Lightfoot's closinganalysis (pp.181-183) of recent research seems to suggest that historicallinguistics be abandoned in favor of comparative linguistics: ''Longobardi... has developed an approach to defining relatedness between systems byquantifying the degree of correspondence among corresponding settings,without invoking reconstructions of any kind of change.'' Such an analysishas nothing to do with how children acquire language. Moreover,Longobardi's analysis (e.g., 2003, 2005) focuses on parameters he hasanalyzed for the syntax of noun phrases, so that languages which appearclose by this method may differ dramatically in parameters for othersaspects of language. I am prepared to believe that such analysis has a roleto play, but stress that this utility holds even if we view UG as a purelydescriptive framework seeking to display a set of variations in thegrammars of human languages and reject the view that UG is an innatecapacity that guides all the essential processes of language acquisitionand thus delimits the set of possible human languages.
In conclusion, Lightfoot's book offers theories of both languageacquisition and language change by assertion. With minor exceptions, hedoes not acknowledge the existence of rival theories and thus offers nodiscussion of data pro or con his own theories. As a result, the case thathis approach will bolster work on historical linguistics seems ill-supported.
REFERENCES
Arbib, M.A., and Hill, J.C., 1984, Schemas, Computation, and LanguageAcquisition, Human Development 27:282-296.
Ayoun, D. (2003) Parameter Setting in Language Acquisition, London: Continuum.
Bean, M., 1983, The development of word order patterns in Old English,London: Croom Helm.
Clahsen, H., & Smolka, K.-D., 1986, Psycholinguistic evidence and thedescription of V2 in German, in Verb-second phenomena in Germanic languages(H. Haider & M. Prinzhorn, Eds.), Dordrecht: Foris, pp.137-167.
Clark, E. (2003) First Language Acquisition, Cambridge: CambridgeUniversity Press.
Clark, R., 1992, The selection of syntactic knowledge, LanguageAcquisition, 2:83-149.
Croft, W., 2000, Explaining Language Change: An Evolutionary Approach,Harlow, England: Longman.
Gibson, E., & Wexler, K.,1994, Triggers, Linguistic Inquiry, 25:407-454.
Holm, J., 2000, An introduction to pidgins and creoles, Cambridge:Cambridge University Press.
Lightfoot, D.W., 1991, How to set parameters: arguments from languagechange, Cambridge, MA: MIT Press.
Lightfoot, D.W., 1999, The development of Language Acquisition, Oxford:Blackwell.
Longobardi, Giuseppe. 2003. Methods in Parametric Linguistics and CognitiveHistory. Linguistic Variation Yearbook 3, 2003, 101-138.
Longobardi, Giuseppe. 2005. A Minimalist Program for ParametricLinguistics? In Organizing Grammar: Linguistic Studies for Henk vanRiemsdijk, ed. by Hans Broekhuis, Norbert Corver, Marinus Huybregts, UrsulaKleinhenz, and Jan Koster. Berlin/New York: Mouton de Gruyter, 407-414.
Pullum, G.K., & Scholz, B.C., 2002, Empirical assessment of stimuluspoverty arguments, The Linguistic Review, 19:9-50.
Senghas, A, 2003, Intergenerational influence and ontogenetic developmentin the emergence of spatial grammar in Nicaraguan Sign Language CognitiveDevelopment 18:511–531.
Senghas A, Kita S, Ozyurek A., 2004, Children creating core properties oflanguage: evidence from an emerging sign language in Nicaragua. Science.305:1779-82.
Tomasello, M., 2003, Constructing a Language: A Usage-Based Theory ofLanguage Acquisition, Cambridge, MA: Harvard University Press.
ABOUT THE REVIEWER
Michael Arbib is a University Professor at the University of SouthernCalifornia. Among his edited and co-edited books are The Algebraic Theoryof Machines, Languages, and Semigroups, (Academic Press, 1968), NeuralModels of Language Processes (Academic Press, 1982), The Handbook of BrainTheory and Neural Networks, (The MIT Press, 1995, 2003), Who NeedsEmotions: The Brain Meets the Robot, (Oxford University Press, 2005), andFrom Action to Language via the Mirror System, (Cambridge University Press,2006).
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