Speech Production in Amharic- Speaking Children with Repaired Cleft Palate Abebayehu Messele Mekonnen A thesis submitted for the degree of Doctor of Philosophy Department of Human Communication Sciences University of Sheffield March, 2013 Abstract Cleft lip/palate is one of the most frequent birth malformations, affecting the structure and function of the upper lip and/or palate. Studies have shown that a history of cleft palate often affects an individual’s speech production, and similar patterns of atypical speech production have been reported across a variety of different languages (Henningsson and Willadsen, 2011). Currently, however, no such studies have been undertaken on Amharic, the national language of Ethiopia. Amharic has non-pulmonic (ejective) as well as pulmonic consonants, which is one of the ways in which it differs from other languages reported in the cleft literature. The aim of this study was therefore to describe speech production features of Amharic-speaking individuals with repaired cleft palate and compare and contrast them with cleft-related speech characteristics reported in other languages. Speech samples were obtained from 20 Amharic-speaking children aged between 5 and 14, with a repaired cleft palate, and a control group of 5 typically-developing children, aged between 4;0 and 6;0, all resident in Ethiopia. Audio and video recordings were made of the participants’ speech production in a variety of contexts including single word production, sentence repetition and spontaneous speech, using a version of the GOS.SP.ASS (Great Ormond Street Speech Assessment: Sell, Harding and Grunwell, 1999) modified for Amharic. A descriptive research design, which involved a combination of perceptual and acoustic phonetic analysis, was employed. The results showed that in addition to the features of speech production associated with cleft palate which are common across languages, there were also language- specific speech production characteristics related to the phonetic and phonological system of Amharic. The atypical speech production patterns identified here suggest that Amharic-speaking children with cleft palate employed various strategies in order to manage the particular speech production challenges posed by the Amharic i phonological system. In particular, in maintaining segmental contrasts, they exhibited a range of unusual airstream mechanisms. In common with children speaking other languages, the children in this study used a range of ingressive articulations (clicks and implosives) in order to avoid nasal escape of air during segmental articulation. Also, however, for ejective versus pulmonic contrasts, they used various atypical realisations (e.g., a preference for glottal realisations of ejectives) and atypical airstream mechanisms (e.g., realisation of ejectives as pulmonics). ii Dedication This thesis is dedicated to my mother, Adanech Birhanu, an astoundingly strong woman , whose advice to work hard at everything I do, to never be afraid to fail, to try and to persevere through difficult times has remained my most important asset! Thanks, Adi! You are the best mom anyone could ever ask for. iii Acknowledgements First and foremost, I would like to thank God whose many blessings have made me who I am today. I would also like to thank everyone who has helped me during my studies. I would not have started and completed this journey without the endless wisdom, advice, and support of my supervisors Prof. Sara Howard, Prof. Mick Perkins and Prof. Bill Wells. Sara’s mentorship was paramount in providing a well-rounded experience consistent my long-term career goals. She taught and encouraged me not only to grow as a phonetician but also as a good teacher and an independent thinker. I am also amazingly fortunate to have a supervisor and personal tutor like Mick. In addition to his guidance and insights, I have also benefited a lot from the pastoral support that he has been providing me with all the way through. I really thank him for everything he has done for me. I have also enjoyed Bill’s wonderful ideas and guidance, approachability, positive outlook, and great efforts to explain things clearly and simply, among other things. I feel so privileged to have him as my supervisor. I am also indebted to Dr. Moges Yigezu and Prof. Baye Yimam and other members of the department of Linguistics, Addis Ababa University, who have played important roles in my academic and research development during this program. In particular, I am very grateful to Dr. Moges, who has supported me personally and professionally since I was a second year undergraduate student in the department. I would also like to thank the staff members of Yekatit 12 Hospital Cleft and Burn Unit and Speech-Language therapy unit, including Dr. Yohannes Demissie, Dr. Mekonnen Eshete, Mesay Gebrehanna, Hirut Mengistu and Shemelis Ejjiɡu for their support during and after data collection. iv I am also very grateful to the children who participated in this study and to their families. I owe a large debt of gratitude to Derib Ado, a colleague at Addis Ababa University, for providing me with his PhD thesis for reference and for his insightful ideas. I also thank Abel Biruk for helping me with the phonetic transcription and perceptual rating reliability testing process. I could not have gained as much in this program without my fellow students who have both inspired and guided me during this experience. I am indebted to the University of Sheffield for funding my studies. Finally, and most importantly, I would like to thank my fiancée Nati Gebre. Her support, encouragement, quiet patience and unwavering love were immeasurable. Her tolerance of my occasional unpleasant moods is a testament in itself of her unyielding devotion and love. I thank my family. My mother, Adanech Birhanu, and, my father, Messele Mekonnen, who have always loved and supported me. They taught me to work hard for the things I want, and I cannot thank them enough just for that. They never gave me/us the notion that education was an option, but rather a goal to be completed. I also thank my uncle, Tamirat Taffesse, who has been a tremendous source of support and encouragement. My cousin, Daniel Damtew also deserves a credit for his inspiration and setting a good example in our family. I cannot mention everyone who mean a lot to me and have supported me, but I want to state that I am very grateful to them all. v Author’s Declaration I hereby acknowledge that the work contained in this thesis is my own original work and has not previously in its entirety or in part been submitted to any academic institution for degree purposes. ___________________________________ Abebayehu Messele Mekonnen December, 2012 vi Table of Contents Abstract…… ................................................................................................................. i Acknowledgements ..................................................................................................... iv Author’s Declaration ................................................................................................... vi Table of Contents ....................................................................................................... vii List of Tables and Figures .......................................................................................... xv Chapter 1: Introduction ............................................................................................ 1 1.1. Cleft lip and cleft palate ............................................................................................... 1 1.2. Aetiology ...................................................................................................................... 2 1.3. Incidence ...................................................................................................................... 3 1.4. Classification ................................................................................................................ 4 1.5. Effects .......................................................................................................................... 6 1.6. Cleft lip/palate in Ethiopia ........................................................................................... 6 Chapter 2: Speech development and cross-linguistic differences ........................ 11 2.1. Introduction ................................................................................................................ 11 2.2. Speech after cleft repair ............................................................................................. 13 2.3. Pre-speech vocalisations and babbling ....................................................................... 14 2.3.1. The relationship between pre-speech and early speech ................................. 16 2.3.2. Onset of first words and later speech ............................................................ 21 2.4. Phonetics and phonology ........................................................................................... 22 2.4.1. Articulation ................................................................................................... 26 2.4.2. Phonology ..................................................................................................... 31 2.5. Cross-linguistic differences ........................................................................................ 33 2.6. Summary ...................................................................................................................
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