The Nature of Specific Language Impairment: Optionality and Principle Conflict
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The Nature of Specific Language Impairment: Optionality and Principle Conflict Lee Davies Thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy University College London August 2001 ProQuest Number: U642667 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest. ProQuest U642667 Published by ProQuest LLC(2015). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code. Microform Edition © ProQuest LLC. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 *I see nobody on the road,* said Alice. 7only wish I had such eyes,* the King remarked in a fretful tone. * To he able to see Nobody! And at that distance too! Why it*s as much as I can do to see real people, by this light!,... ABSTRACT This thesis focuses upon two related goals. The first is the development of an explanatory account of Specific Language Impairment (SLI) that can effectively capture the variety and complexity of the children’s grammatical deficit. The second is to embed this account within a restrictive theoretical framework. Taking as a starting point the broad characterisation of the children’s deficit, developed by Heather van der Lely in her RDDR (Representational Deficit for Dependant Relations) research program, I refine and extend her position by proposing a number of principled generalisations upon which a theoretical explanation can be based. These generalisations embody three specific claims; that SLI is a disorder that affects both productive and receptive language, that SLI children’s errors are mainly errors of omission and not commission, and that even the children’s ungrammatical production is representative of their grammar. I motivate these claims and consider how they might inform the development of a theoretical account of the disorder. My theoretical proposals are based on the concept of Principle Conflict. I propose that the SLI child’s grammar contains two principles which conflict in a way that makes them each select different optimal derivations from a given lexical array. As a result of this conflict, the child optionally produces a range of constructions which are ungrammatical for the Normal Development grammar. My proposals make a number of empirical predictions for the children’s speech. I present findings from a range of experimental studies which test many of my predictions for the domain of syntactic Negation. Negation is examined because it is a relatively new area of research and provides a range of interesting diagnostics for the particular syntactic phenomena which is my interest. Finally I consider the implications of my findings for my explanatory account. I also examine some of the most recent theoretical developments in the Minimalist program and discuss how my account can accommodate these. Now my thesis is done, I should take this time to thank the people who helped make it possible. First of all, I want to thank my teacher, Neil Smith. It has been an honour to work under his supervision. Neil’s dedication to his students and to linguistics is incredible. He has consistently inspired me and I have never left his office without feeling a little better about myself and the world in general. My main regret is that now I’m finished I won’t see him as often. However, he really should get an office lower down the building, all those steps! I tried counting them in base 12 as he suggested, but it doesn’t help. Next, I would like to thank Heather van der Lely, my second supervisor. Heather is one of the people I most admire in our research field. It was her vision and help that both inspired my research project and made it possible. She has always been ready to offer advise and new perspectives for which I will be forever grateful. I want to thank the children who participated in the study and their parents and teachers. In particular, I would like to thank the staff and pupils at the Moorhouse school, Hurst Green; Glebe Infants and Picklenash Juniors, Newant; and Buxton Community School, Buxton. They were great company and page turners. There are so many people at UCL who have helped me, here are just some of them: Ad Neeleman, Alex Perovic, Amela Camdzic, Annabel Cormack, Demetria Papangeli, Eleni Gregoromichelaki, Georgia Panitsa, Hans van der Koot, Hye-Kyung Kang, Karen Proud, Kristza Szendroi, Sam Martin, Vina Tsakali, and all the regulars at the Minimalist Reading Group. Last, but not least, Dirk Bury. Dirk is not just a beard (now I don’t even notice it!). He also makes great food, and knows almost every second hand book shop in London. Thanks for putting up with my inane ramblings and being my cinema companion (and he’s quite a good linguist too). If I forgot anyone. I’m really sorry. Please insert your name here _________ . From the Linguistics Department at Bangor, three people’s names particularly stand out; Bob Borsley, Margaret Deuchar, and Anna Roussou. Bob and Margaret were both my supervisors at Bangor and I’m grateful for their help and wise guidance. Anna was another guiding light in my development as a linguist. During my time at Bangor, I took nearly all her classes, some twice. Thanks for some of the most enjoyable linguistics I’ve ever done. Some people in London still need to be mentioned. First is Melanie Jones, (formally at Birkbeck) who should be given an award for teaching me how to use SPSS in 8 hours, and Jackie Battel (also formally at Birkbeck) who first took me to Moorhouse to meet the kids. My flat mates at Clandon House: Bernard, Jangho and particularly Sukant, a true friend. Thanks for the late night games of scrabble. I’m ashamed to say that although I was the only native speaker of English in the flat, I never won once -perhaps next time. Now back to home. I’d like to thank two people from my past who both had strong influences on me; Pat White and Paul Black. Also my old friends Lee, James, Timon, and Paul, Jo and Nathan. Now my family; thanks to my Grandparents, particularly my Grandmas (who feature in my examples). Thanks to my brother, Sean and my Mum and Dad, who have supported me unfailingly all the way. I hope I can live up to your example. Finally, Rebecca. There is so much that I have to thank her for. Over the past four years she has constantly supported me with love and advice. I can truly say that I couldn’t have done it without her. You unclose me Becca. This thesis is dedicated to you. TABLE OF CONTENTS Chapter 1 1. Introduction ..................................................................................................... 11 1.1 Approach to SLI ................................................................................... 12 1.2 Theoretical basis ............................................................................................. 13 1.2.1 The components of the language faculty ......................................... 14 1.3 Organisation of the thesis ................................................................................ 16 Chapter 2 2.1 The nature of S L I ............................................................................................. 19 2.1.1 Clinical definition ................................... 19 2.1.2 The prevalence of S L I ................................................................ 20 2.1.3 The genetics of SLI ........................................................................... 20 2.1.4 The neurobiology of SLI .................................................................. 22 2.1.5 Subgroups of SLI ........................................................................ 24 2.2 Characterising SLI: the grammatical deficit .....................................................26 2.2.1 Morphology ....................................................................................... 26 2.2.2 Errors of syntactic structure ............................................................. 27 2.2.3 Wh- questions ................................................................................... 29 2.2.4 C ase.................................................................................................... 30 2.3 Accounts of S L I ............................................................................................... 31 2.3.1 Processing accounts: The Surface Hypothesis and The Sparse Morphology Hypothesis ................................................ 32 2.3.2 Grammatical accounts of SLI ........................................................... 35 2.3.2.1 Accounts of the morphological deficit ...........................................35 2.3.2.1.1 The Rules Formation Deficit Account ............................ 35 2.3.2.1.2 The Agreement Deficit Account ......................................37 2.3.2.1.3 The Extended Optional Infinitive Account ......................39 2.3.2.2 Broader deficit accounts ............................................................... 41 2.3.2.2.1 The Representative Deficit for Dependent Relations (c.f. van der Lely 9 6 ) ............................................................................41 23.2.2.2 The Impaired D-System Account (Tsimpli & Stavrakaki 9 9 ) ..................................................................