Research On The Tongue Movement Of The Pronunciation Of Tibetan Vowels In Lhasa Based On Ultrasonic Detection

Based on the framework of Articulatory Phonology and coarticulatory theory,this dissertation studied the tongue shape of vowels and coarticulation between vowels and consonants in Lhasa Tibetan.It is a trail study of physiological articulatory study in minority languages using physiological instruments.The dissertation consists of six chapters.Chapter one first gives an overview on the research background,current theories or models on Articulatory Phonology and coarticulatory theory.The research results of tongue shape of vowels and the research results of coarticulation between vowels and consonants are also summarized.Chapter two introduces the experimental design and research methods.Firstly,the research questions and hypotheses of this dissertation are put forward,and then the specific experimental methods are introduced in detail,including the experimental tools,experimental corpora,experimental objects,operating procedures,and later data processing methods.Chapter three uses ultrasound image to observe the tongue shape of the five basic vowels /a/,/i/,/u/,/e/,and /o/ in Lhasa Tibetan based on the theory of Articulatory Phonology.We performed SS ANOVA analysis on the tongue shape of the stable part of the vowel,and then obtained the tongue position distribution pattern of the five basic vowels: the tongue position of the vowels /i/ and /e/ are Front Bunched,which are extended from the right to the lower left,the tongue position of the vowels /u/ and /o/ are Back Bunched,which are extended from the left to the lower right,while the tongue positions of the vowel /a/ are No Obvious Bunched,which are relatively centered,and are roughly left-to-right extended.In addition,the tongue gestures of the Lhasa Tibetan vowels are also presented.The tongue tip motion,tongue arching state,and tongue root motion are described respectively,which can help distinguish the differences of tongue shape effectively.Chapter four analyzes the coarticulatary effects of consonants with different manner of articulation and consonants with different place of articulation to vowel gestures in CV sequences.The first part analyzes vowels following labial consonants(p,p?,m),alveolar consonants(t,t?,n,ts,ts?,s),alveolo-palatal consonants(t?,t??,?,?),retroflex consonants(t?,t??,?),palatal consonants(c,c?),and velar consonants(k,k?,?).The second part analyzes vowels following plosives(p,t,k,c),affricatives(ts,t?,t?),fricatives(s,?,?),nasals(m,n,?,?).The comparison of tongue shape differences between vowels is mainly performed by SS ANOVA analysis of tongue position data using R language software package.The main effect curve and interaction curve of tongue shape are observed to analyze the difference between tongue shapes.The last section summarizes the differences of coarticulatory effects of different consonants to vowels.Chapter five analyzes the tongue shape of vowels followed by three nasal endings in CVN sequences.Tongue shape observation showed that the tongue shape of vowels before /m/ and /?/ did not change significantly,while the tongue shape of vowels before /n/ changed.Tongue shapes of vowels in front of /n/ are more forward,tongue tip are raised,and the arched parts are more forward.This is because the elevation and forward extension of the front part of the tongue when pronouncing /n/ pulled the entire tongue forward,overlapping with the gesture target of vowels,and then causing the tongue shape to change,the sound also changed.The gesture target of /m/ and /?/ do not conflict with the tongue shape motion of vowels,so there is no coarticulatory effects on the preceding vowels.Chapter six summarizes the main research issues and preliminary conclusions of this dissertation,and discusses the rules of coarticulation between vowels and consonants and the factors that affect coarticulation.