2016 Conference of The Oriental Chapter of International Committee for Coordination and Standardization of Speech Databases and Assessment Technique (O-COCOSDA) 26-28 October 2016, Bali, Indonesia 978-1-5090-3516-8/16/$31.00 ©2016 IEEE Phonological Realization of English Lexical Stress Placement by Native (L1) Bengali Speakers Shambhu Nath Saha Centre for Educational Technology Indian Institute of Technology Kharagpur, India shambhuju@gmail.com Shyamal Kr. Das Mandal Centre for Educational Technology Indian Institute of Technology Kharagpur, India sdasmandal@cet.iitkgp.ernet.in Abstract— English lexical stress is multidimensional in nature and acoustically related to combination of fundamental frequency (F0), duration, intensity and vowel quality. Current study investigates the acquisition of English lexical stress by L1 Bengali speakers at phonological level. This study compares 20 L1 Bengali speakers’ use of acoustic correlates for production of English lexical stress in context sentence and neutral frame sentence. Result of this study showed that L1 Bengali speakers were not able to achieve neutral frame sentence like control over duration, intensity, F0 and to a limited extent vowel quality in context sentence. This experiment reveals that due to the influence of Bengali phonology of lexical stress placement (restricted to the initial syllable of a word) on L1 Bengali speakers’ English speech, L1 Bengali speakers were not sensitive to contrastive stress pattern in context sentence, unlike neutral frame sentence. Keywords- Lexical stress; acoustic cues; speech prosody; context sentence; neutral frame sentence; vowel quality I. INTRODUCTION Stress is one of the most important suprasegmental features in speech prosody. In linguistics, stress is the relative emphasis that may be given to certain syllables in a word, or to certain words in a phrase or sentence. English is a stress-accent language [1] and English lexical stress is contrastive in nature and related to part-of-speech [2]. At phonetic level, English lexical stress is acoustically related to combination of fundamental frequency (F 0 ), duration, intensity and vowel quality [3]. At phonological level, the location of English stressed syllable depends on factors such as syllable structure and lexical class. If a syllable has a long vowel, it is likely to receive primary stress, and in case of English disyllabic words, the location of stress on first or second syllable led the word to be identified as a noun or a verb respectively [4]. As English continues to grow in importance as a language for international communication throughout the world, it is necessary for L1 Bengali speakers to acquire English language properly. From the theory of second language acquisition, it is suggested that proper acquisition involves in correct production and perception of one of the most important suprasegmental features that is lexical stress; that means nonnative (L2) English speakers need to produce correctly the L2 stress pattern for proper production of English speech. Unlike English, word stress placement in Bengali is restricted to the initial syllable of a word [5] and is not contrastive in nature [6]. Bengali lexical stress is expressed by a combination of pitch, duration and intensity; but stress does not affect vowel quality in Bengali [6]. Although F 0 , intensity, duration serve as cues to lexical stress in Bengali, the stress in a word is dominantly realized by a low rising pitch pattern where the F 0 movement consists of a low F 0 valley followed by a rise [5]. There is very little use of intensity to identify stress in Bengali [7]. There are fundamental differences in stress properties between English and Bengali languages at phonetic and phonological levels. At phonetic level, vowel quality does not serve as acoustic cue of Bengali lexical stress unlike English, results in lack of vowel reduction in unstressed syllables in Bengali. Our previous study [8] of phonetic realization of English lexical stress by L1 Bengali speakers showed that L1 Bengali speakers used the acoustic correlates of vowel duration, intensity and F 0 in English like manner. Moreover, L1 Bengali speakers produced English like vowel quality in certain unstressed syllables, but in other cases there were significant differences in vowel quality across groups. As a result, Bengali speakers produced significantly less English like stress patterns. This was due to interference from L1 to L2 phonology. At phonological level, Bengali differs from English in that Bengali is bound stressed language, but the occurrence of the strongest stress at the beginning of a word is not a phenomenon appearing very commonly in English. When an L2 speaker discerns differences between L1 and L2 stress patterns, a possibility of language transfer arises. As a result, language transfer may occur at both phonetic and phonological levels, and causes difficulties in the correct production of specific L2 (English) stress patterns by L1 Bengali speakers. The current study focuses on L1 Bengali speakers’ acquisition of phonological rules of English lexical stress placement. The objective of this study is to investigate the phonological realization of English lexical stress placement by L1 Bengali speakers. For this purpose, examine the differences between the uses of acoustic correlates of English lexical stress by L1 Bengali speakers under the conditions, where the position of stress to be placed in the target words in context sentence was unknown and the position of stress to be placed in the target words in neutral frame sentence was known to L1 Bengali speakers.