Acoustic Analysis of Native ( L 1) B engali Speakers’ Phonological Realization of E nglish Lexical Stress Contrast (2020)

Abstract: Acoustically, English lexical stress is multidimensional and involving manipulation of duration, intensity, fundamental frequency (F0) and vowel quality. The current study investigates the acquisition of English lexical stress by L1 Bengali speakers at the phonological level in terms of the properties of acoustic cues. For this purpose, this study compares 20 L1 Bengali speakers’ use of acoustic correlates for the production of English lexical stress in context sentence and neutral frame sentence. The 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. As a result, unlike neutral frame sentence, L1 Bengali speakers were not sensitive to English lexical stress contrast in context sentence. This analysis reveals that, the difference between the neutral frame and context sentences in terms of L1 Bengali speakers’ realization of phonology of English lexical stress contrast was probably 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.

## 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 @xcite and english lexical stress is contrastive in nature and related to part-of-speech @xcite . at phonetic level, english lexical stress is acoustically related to combination of fundamental frequency (f0), duration, intensity and vowel quality @xcite . 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 @xcite . 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 the english language properly. from the theory of second language acquisition, it is suggested that proper acquisition involves in correct production of one of the most important suprasegmental features that is lexical stress @xcite . unlike english, word stress placement in bengali is restricted to the initial syllable of a word @xcite and is not contrastive in nature @xcite . bengali lexical stress is expressed by a combination of pitch, duration, and intensity; but stress does not affect vowel quality in bengali @xcite . although f0, 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 f0 movement consists of a low f0 valley followed by a rise @xcite , and there is very little use of intensity to identify stress in bengali @xcite . there are fundamental differences in stress properties between english and bengali languages at phonetic and phonological levels. at phonetic level, unlike english, vowel quality does not serve as the acoustic cue of bengali lexical stress. saha and mandal (2015) previously showed that l1 bengali speakers used the acoustic cues of vowel duration, intensity and f0 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 (nonnative) at the phonetic level. 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. this leads to major problems with acquiring correct stress placement habits for l1 bengali speakers in their english speech. the current study concentrates on the acquisition of phonology of english lexical stress placement by l1 bengali speakers. the objective of this study is to investigate the realization of the phonology of english lexical stress by l1 bengali speakers who were fluent in english. 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. ## conclusions from the results of this study, it appears that l1 bengali speakers showed a substantial difference in use of the acoustic correlates of vowel duration, intensity, and f0 of english lexical stress between the neutral frame and context sentences. but, l1 bengali speakers did not show the significant difference in vowel quality of stressed syllable between the neutral frame and context sentences and l1 bengali speakers reduced vowel in the unstressed syllable with a similar degree and quality in both types of sentences. this acoustic analysis reveals that l1 bengali speakers were not able to achieve neutral frame sentence like control over duration, intensity, f0 and to some extent quality of stressed and unstressed vowels in context sentence. this difference between both types of sentences was probably due to the interference from bengali phonology of lexical stress placement on l2 english, where l1 bengali speakers' tendency was to put stress on the first syllable of each disyllabic target word in context sentence without recognizing its lexical stress contrast. hence, results of this acoustic analysis suggest that, although l1 bengali speakers were able to produce lexical stress contrast in neutral frame sentence in an english-like manner, they were not sensitive to english lexical stress contrast in context sentence.