The Effect of Articulatory Constraints and Auditory Information on Patterns of Intrusions and Reductions. By Anneke W. Slis A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy Department of Speech Language Pathology Oral Dynamics Lab University of Toronto © Copyright by Anneke Slis 2014 The Effect of Articulatory Constraints and Auditory Information on Patterns of Intrusions and Reductions Anneke W. Slis Doctor of Philosophy Department of Speech Language Pathology University of Toronto 2014 Abstract This dissertation seeks to answer the question whether articulatory constraints and auditory information affect intrusion and reduction errors. These intrusions and reductions of articulatory movement result from a general tendency to stabilize movement coordination. Stabilisation of speech movement coordination is an autonomous self-organizing process. This process, however, can be affected by factors related to articulatory properties and auditory information. To assess how these factors affect movement coordination, three studies were performed. The first study examined differences in articulatory variability in the onsets of word pairs such as cop top and top top. To this end, different phonetic contexts and speaking rate were manipulated. As word pairs like top top are frequently used as control stimuli and word pairs like cop top as experimental stimuli, this study investigated how these two word pairs differ in movement control. The second study examined how constraints on individual articulators, manipulated by phonetic context, and speaking rate affected the number of intrusions and reductions. The third study investigated how these intrusions and reductions were influenced by the presence or absence of auditory information. Movements of the tongue tip, tongue dorsum ii and lower lip were recorded with electromagnetic articulography. The first study revealed that word pairs with alternating and identical onset consonants differ to such an extent that using identical onset word pairs as control stimuli is not recommended for future error studies. The second study revealed that articulatory constraints resulted in asymmetrical patterns of intrusions: compared to a high back vowel context, a low vowel context resulted in more intrusions in general. In addition, in a front vowel context, the tongue dorsum intruded more frequently than the tongue tip and lower lip. The third study showed that speakers made fewer intrusions without auditory information available than with auditory information available. The results, which are explained within the framework of Articulatory Phonology and Task Dynamics, support the notion that articulatory constraints and auditory information influence coupling strength and movement coordination as reflected in intrusion and reduction patterns. iii Acknowledgments I would like to extent my deepest gratitude to my graduate advisor Pascal van Lieshout and committee members Keren Rice and Jeffrey Steele. Only with their extensive knowledge and feedback was I able to develop my understanding of an, to my opinion, extremely complicated area of speech science. Pascal van Lieshout has been an unbelievable source of knowledge and an extremely patient mentor in the whole process leading up to this final version of my dissertation. Keren Rice and Jeffrey Steele have been tremendously supportive in their theoretical contributions and during the many revisions of the manuscript. The technical assistance from Aravind Namasivayam, Konstantin Alexandrovych and James Le made it possible to collect the data I needed for my thesis, which Radu Craioveanu, without complaining, helped analyzing. I’m very grateful to Mark Noseworthy’s voice recordings and to all the patient participants, who dedicated several hours of their lives repeating word pairs. Celine Miller was a great support in finding and scheduling new participants. Toni Rietveld and Barbara Reid helped in statistical and the editing process for chapter 2. I also wish to thank the University of Toronto and the department of Speech Language pathology in providing me with ample financial support in the form of fellowships and awards to be able to attend complete my PhD. A special thank you goes out to Sieb Nooteboom, who, before I entered the University of Toronto to pursue my PhD degree, introduced me to the fascinating world of speech errors. On several occasions, I had the opportunity to reflect on my designs with Louis Goldstein and Marianne Pouplier, which has been extremely helpful. Of course, their work on intrusions and reductions has led to this dissertation. I’m also thankful to my friends inside and outside the world of academia who directed me back to real life when nessecary. I wish to thank my family, iv in particularmy two children, Lotte and Tim, and a partner, Tedde, who kept me with two feet on the ground and reminded me what life was really about.Thank you! v Table of Contents LIST OF TABLES ....................................................................................................................... X LIST OF FIGURES ................................................................................................................ XIII 1 CHAPTER 1 ......................................................................................................................... 1 1.1 INTRODUCTION .................................................................................................................... 1 1.2 PERCEPTION STUDIES: SEGMENTAL ERRORS ......................................................................... 5 1.3 ACOUSTIC AND KINEMATIC STUDIES: SUB-SEGMENTAL ERRORS ........................................ 10 1.4 THE TASK DYNAMIC MODEL AND ARTICULATORY PHONOLOGY ...................................... 16 1.4.1 General characteristics ............................................................................................ 16 1.4.2 The inter-gestural coordination level ....................................................................... 18 1.4.3 The inter-articulator coordination level ................................................................... 20 1.5 INTRUSIONS AND REDUCTIONS IN TASK DYNAMICS ........................................................... 24 1.6 STUDIES AND HYPOTHESES................................................................................................ 32 1.6.1 Study 1 ...................................................................................................................... 32 1.6.2 Study 2 ...................................................................................................................... 34 1.6.3 Study 3 ...................................................................................................................... 35 1.6.4 Methods..................................................................................................................... 35 1.7 REFERENCES ...................................................................................................................... 38 2 CHAPTER 2 ....................................................................................................................... 52 2.1 ABSTRACT ..................................................................................................................... 54 2.2 INTRODUCTION ............................................................................................................ 55 2.2.1 Background ............................................................................................................... 55 vi 2.2.2 Current Study ............................................................................................................ 58 2.3 METHODS ....................................................................................................................... 60 2.3.1 Participants............................................................................................................... 60 2.3.2 Stimuli ....................................................................................................................... 61 2.3.3 Procedures ................................................................................................................ 62 2.3.4 Instrumentation ......................................................................................................... 64 2.3.5 Data Processing........................................................................................................ 65 2.3.6 Analysis ..................................................................................................................... 67 2.4 RESULTS ......................................................................................................................... 70 2.4.1 Median Movement Range ......................................................................................... 70 2.4.2 Variability ................................................................................................................. 72 2.4.3 Correlation Values.................................................................................................... 74 2.5 DISCUSSION ................................................................................................................... 75 2.6 ACKNOWLEDGEMENTS .............................................................................................. 80 2.7 APPENDIX .....................................................................................................................