| Stress is one of the important suprasegmental features.The distribution of sentence stress has a great influence on the naturalness and accurate interpretation of utterances.English is a typical stress-timed language while Chinese is a syllable-timed language.This difference often results in difficulty for Chinese EFL learners in acquiring of English sentence stress.The thesis reports an investigation into the prosodic transfer effects of Cantonese tendencies on English sentence stress acquisition for learners of English,aiming to assist Cantonese EFL learners to improve their utilization of English sentence stress.Twenty Cantonese EFL learners are involved in the phonetic experiment,whose production of sentence stress is compared with that of a native speaker of American English.The measurement tool is the commonly used phonetic software Praat.With analysis based upon this phonetic experiment,the study attempts to ascertain the distribution of English sentence stress by Cantonese EFL learners within the framework of Optimality Theory,giving an account for the mechanism of the sentence stress acquisition in terms of the hierarchical ranking of constraints.The findings reveal that(1)compared with the native English speaker,Cantonese EFL learners assign stress to more words in attributive clauses as each syllable seems to achieve similar degree of prominence,resulting in the deficiency of rhythmic variations in sentences;(2)Results of the phonetic experiment indicate that duration and pitch are the main acoustic parameters in realizing stress by Cantonese EFL learners.The stressed words are characterized by longer duration and greater change in pitch value.As sentences become longer,pitch contours get more jagged thus the distribution of sentence stress becomes random.Moreover,Cantonese subjects use too many pauses in attributive clauses,and some of them are confused in chunking with regard to the subordinator “that”;(3)Within the framework of OT,six constraints are involved to explain stress allocation in that-initiated attributive clauses.For English native speakers,the constraint hierarchy of sentence stress distribution is: Dep-IO(P)>>No Clash>>No P(OI)>>Max-IO(P)>>Align-R-IP(P)>>Align-L-IP(P).Cantonese EFL learners undergo a process of re-ranking of these constraints in their sentence production that differs from native English speakers.The constraint ranking for Cantonese EFL learners is: Max-IO(P)>>Dep-IO(P)>>No Clash>>No P(OI)>>AlignR-IP(P)>>Align-L-IP(P).The promotion of the markedness constraint Max-IO(P)suggests that Cantonese EFL learners take priority over the principle of content words stressed in the acquisition of sentence stress.The present study is an investigation into the underlying mechanism governing the acquisition of sentence stress for Cantonese EFL learners on the basis of OT.It sheds light on research in the field of second language acquisition and provides guidance for English phonetic teaching in China. |
