THE ACQUISITION OF VERBAL INFLECTION IN CHILD GRAMMARS IN A VARIABILITY MODEL OF EARLY MORPHOSYNTACTIC DEVELOPMENT : A BIOLINGUISTIC PERSPECTIVE A Dissertation submitted to the Faculty of the Graduate School of Arts and Sciences of Georgetown University in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Linguistics By Dominik Rus, B.A. Washington, DC April 11, 2008 Copyright 2010 by Dominik Rus All Rights Reserved ii THE ACQUISITION OF VERBAL INFLECTION IN CHILD GRAMMARS IN A VARIABILITY MODEL OF EARLY MORPHOSYNTACTIC DEVELOPMENT : A BIOLINGUISTIC PERSPECTIVE Dominik Rus, B.A. Thesis Advisors: Donna Lardiere, Ph.D. and Charles Yang, Ph.D. ABSTRACT This dissertation investigates the acquisition of early verb inflection in child Slovenian from morphosyntactic and morphophonological perspectives. It centers on the phenomenon of root nonfinites, particularly the patterns of omission and substitution errors in verb inflection marking. It argues that every acquisition model needs to account for the following robust developmental phenomena: initial telegraphic speech, optionality, variability, graded (rather than absolute) morpheme order, and gradualness. It suggests that current biolinguistic models can be enhanced by supplementing evidence from UG-based studies with that from usage-based and neuropsychological accounts. This proposal is tied to Chomsky’s (2005) hypothesis that language comprises three factors —the innate language faculty, experience, and computational efficiency, and that language acquisition relies considerably on this third factor. The study motivates the Inflectional Hierarchy Complexity Hypothesis (IHCH), suggesting that while children’s early morphosyntax is adultlike regarding the availability of iii functional categories and the concatenation operation, children’s morphophonological spell-out is unreliable due to computational bottlenecks. It is hypothesized that grammars initially contain verbs which may be disguised as adultlike finite forms with minimal or zero morphology (e.g., 3 rd singular present [3S] reported in early Romance). Such verbs are arguably vPs and are morphophonologically spelled out with greater success than tensed forms which, in turn, are more successful than person-based forms. That is, a probabilistic hierarchy of bare stems > tensed forms > person agreement verbs is predicted, where the forms to the left are postulated to be spelled out statistically better than those to the right. Based on lemmatization and frequency counts and syntactic and morphophonological analyses of existing and new child Slovenian data, the study confirms the IHCH. It is shown that early Slovenian verbs are mainly complex bare verbs (CBVs) that carry only the conjugation class morphology with no person/number inflection —homophonous with 3S forms —and past participles that lack auxiliaries (arguably TNSPs). Person-related inflection is supplied statistically less reliably than participle inflection which, in turn, is less reliable than the inflection on CBVs. This hierarchy is observed even at age 2;5+ when overt inflection is supplied 80%-90% of the time and most morphophonological properties have been acquired. iv PREFACE If we knew what it was we were doing, It would not be called research, would it? - Albert Einstein - Soon after I started graduate school I co-founded (with Pritha Chandra from the University of Maryland) the Biolinguistics Reading Group for the Georgetown University and University of Maryland at College Park research communities, advocating a greater understanding of linguistics as a natural science, and —particularly —fostering an interdisciplinary approach in our endeavors to study language and its development. Hoping to attract a wide variety of scholars working in computer science, linguistics, neuroscience, and psychology, and craving for a dynamic, intellectual, and stimulating crowd, I invited David Lightfoot, Massimo Piatelli-Palmarini, and Juan Uriagereka —all distinguished, top-notch scientists in their respective fields. The response exceeded our expectations: the group started with some twenty biologists, neuroscientists, psychologists, and linguists from various backgrounds (from syntacticians, semanticists, and computational linguists, to cognitive linguists interested in input and interaction in second language acquisition). Only for a few weeks, though. For the next year or so, it would be Pritha and I, together with four theoretical linguists and psycholinguists from UMD, discussing anything from the evolution of minimalist syntax to the FOXP2 gene while sipping coffee and munching on chocolate chip cookies. I thoroughly enjoyed our informal colloquies, but I personally mainly realized how unquestionable a lot of linguistic theorizing has been, how many ad hoc proposals linguists have taken for granted, and —particularly —how much conflicting evidence there has been in the field. The more I knew about minimalist syntax, the more I was buying the story of “narrow syntax” being distinct from some broader language capacity that interacts with other non-linguistic, more general cognitive domains. In the same vein, the more I read about generative language acquisition, the more I found myself steering away from the “mainstream” generative credo of parameterized learning that brought me quite a few accolades as an undergraduate student and characterized a great bulk of my studies and research as a novice graduate student. Numerous conferences and the interaction with various professors, postdocs, and graduate students in the Departments of Linguistics, Psychology, and Neuroscience at Georgetown and Linguistics and Neuroscience at UMD, as well as my interaction with the students and postdocs in the Brain and Language Lab at Georgetown have all sharpened my thinking about language and its acquisition. Though still a generative linguist at heart, I v realized that I have become quite “radical” in my thinking about language acquisition. The drive for the biolinguistics group eventually waned out and now it was just Pritha and I, scribbling notes on Starbucks or Panda Express paper napkins and defending our views —Pritha generally defending the “classic” Chomskian program and sometimes calling me “maybe too radical”, and me generally objecting to too deterministic linguistic formal acquisition accounts and various constraints and parameters that were multiplying by the dozen every time Chomsky would update his theory or another Linguistic Inquiry issue would come out. This investigation has grown particularly from my reaction to numerous UG-based accounts of child morphosyntactic and morphophonological phenomena that have put forth myriads of descriptive, extemporaneous principles that —I believe —have had little explanatory power and would as such almost always be immediately superseded by subsequent technological tweaks coming from formal linguistic theories. I have always argued that evidence from language acquisition should inform linguistic theory in explaining various linguistic phenomena rather than undergo a rigorous test whether a certain technology is successful since the latter approach always runs into a risk of attributing mere technology to our biological linguistic endowment a priori . Moreover, I have argued —within the scope of biolinguistics, though —that fruitful research into language acquisition will be the one that bridges linguistic insights with those from neurocognitive and developmental psychological research. This dissertation shows that each body of research has contributed an important array of tools and evidence on human language acquisition and —most importantly —that neither line should be undertaken in the absence of the other. I believe that nowadays with so much substantial evidence from formal linguistic theories, psycholinguistic theories of language processing and development, computational modeling, as well as evidence from brain imaging research, we cannot but agree that language acquisition is a dynamic interplay between biology and learning or —following Chomsky’s (2005) thesis —an interplay between biology, experience, and computational efficiency. vi ACKNOWLEDGEMENTS I have been fortunate to have met many great scholars and to have made so many great friends since I first set foot in the Graduate School at Georgetown. Donna Lardiere became my first role model in linguistics. Not only did she teach me how to reason and write as a linguist and acquisitionist, she would always support me and listen to my whining about DC weather, work overload, missed plane connections, or overpriced coffee at the school cafeterias. She became my academic advisor on Day 1 and stayed with me until the very end, serving as my dissertation co-director. A lot of ideas in this dissertation grew from our numerous chats about language development. Her great intellect sharpened my thinking about language and she would always dot the i’s and cross the t’s on pretty much anything I’d hand in —be it a piece of homework, a paper for presentation or publication, or dissertation chapters. Donna, you rock! I am forever indebted to you! Héctor Campos has always been my “syntax hero” —he has read literally hundreds of pages of my syntax and acquisition writing throughout several years and guided me through every single step of being a good syntactician —from gathering and sorting out data to rigorous analysis and persuasive argumentation. He is a superb linguist and a fantastic teacher, always trying to make sure that the syntax in