Speech Perception Performance of Native Speakers of Marathi: Effect of Filtered Speech Stimulus and Degree of Hearing Impairment S. B. Rathna Kumar Ali Yavar Jung National Institute of Speech & Hearing Disabilities (Divyangjan), Mumbai, India Niharika Dash Institute of Health Science, Bhubaneshwar, India Mendem Bapuji MAA Institute of Speech & Hearing, Hyderabad, Telangana, India S. Arulmozi Center for Applied Linguistics & Translation Studies, University of Hyderabad, India Chandrahas Chandanshive B. Y. L. Nair Charitable Hospital & Topiwala National Medical College, Mumbai, India Abstract—The study investigated the effect of filtered speech stimulus on speech perception performance of native speakers of Marathi as a function of degree of hearing impairment. Speech identification score (SIS) testing was performed to measure speech perception on three groups (Group I, Group II, and Group III consisted of participants with moderate, moderately-severe, and severe sensorineural hearing impairment respectively). Speech stimuli comprised eight word-lists with each list consisting of 25 words in Marathi. The first seven word-lists (first to seven) were filtered at 500 Hz, 1000 Hz, 1500 Hz, 2000 Hz, 2500 Hz, 3000 Hz, and 3500 Hz cut-off frequencies, respectively, while word list 8 was left unfiltered. Although, the SIS improved with increase in cut-off frequency, the improvement in SIS with increase in cut-off frequency of speech stimulus was noticed up to 3000 Hz, 2500 Hz, and 2000 Hz for participants of Group I, Group II, and Group III, respectively. In addition, the improvement in speech perception performance did not correspond to what would be anticipated with an increase in the cut-off frequency of speech stimulus for participants of Group II and Group III compared to participants of Group I. Although, there was a significant reduction in SIS as a function of the degree of hearing impairment for speech stimulus filtered at 1500 Hz, 2000 Hz, 2500 Hz, and 3000 Hz cut-off frequencies, there was no significant effect of degree of hearing impairment on SIS for speech stimulus filtered at 500 Hz and 1000 Hz cut-off frequencies. Index Terms—filtered speech stimulus, degree of hearing impairment, cut-off frequency, speech identification score, Marathi I. INTRODUCTION Speech is one of the most important vehicles of human communication systems, and hearing is the building block upon which our complex communication system is designed. The perception of speech is most generally assessed in terms of an individual's auditory capability to recognize regular components of speech such as phonemes, words, and sentences (Winn, Won & Moon, 2016). There are several spectral and temporal variations in the speech which contribute to the perception of speech signals across languages (Avilala, Prabhu & Barman, 2010). Thus, speech perception is influenced by how psychophysical properties of speech, such as spectral and temporal features, are identified and distinguished, which is in turn influenced by a person's auditory capability (Win, Won & Moon, 2016). A systematic study is therefore required to determine the significance of spectral and/or temporal features of speech for speech perception. The significance of spectral or temporal features to speech perception can be explored by altering one parameter while leaving another unaltered. Thus, one can study the contribution of different spectral components of speech in speech perception by manipulating the spectral properties of speech, such as the use of filtered speech stimulus (Avilala, Prabhu & Barman, 2010). Similarly, the contribution of temporal components of speech in speech perception can be studied by manipulating the temporal characteristics of speech, such as time-compressed speech stimulus (Bhargavi, Prakash, Kumar & Sindhura, 2011). Bornstein, Wilson & Cambron (1994) investigated the effect of filtered speech on speech identification performance of native speakers of English and observed that individuals with normal hearing obtained 70% SIS for speech stimuli ISSN 1799-2591 Theory and Practice in Language Studies, Vol. 12, No. 2, pp. 230-240, February 2022 DOI: https://doi.org/10.17507/tpls.1202.03 © 2022 ACADEMY PUBLICATION