Native and non-native listeners’ speech comprehension performance under adverse listening conditions

Jayanthiny Kangatharan1, Maria Uther2 & Fernand Gobet3

1. Brunel University
2. University of Winchester
3. University of Liverpool 

There is an abundance of literature on the effects of clear speech and intelligibility (e.g. Bradlow & Bent, 2002; Bradlow et al., 2003). However, intelligibility may not always concord with speech comprehensibility (Hustad & Beukelman, 2002). Comprehension assesses a listener’s ability to construe the meaning of an acoustic signal in order to be able to answer questions about its contents while intelligibility indicates the extent to which a listener can precisely retrieve the acoustic signal (Hustad, 2008). It is notable that previous comprehensibility studies that were administered to ask listeners for sentence-level information (Hustad & Beukelman, 2002) or narrative-level information (Hustad, 2008) were presented to native listeners. No research has been done on which clear speech properties (e.g. expanded vowel space) produce a clear speech benefit at word level for L2 learners for speech produced in naturalistic settings. This study explored whether expanded vowel space in target word items from a Diapix task were more comprehensible for both L1 British English speakers and early and late L2 British English learners in quiet and in noise. Sixteen British English listeners, 16 native Mandarin Chinese listeners as early learners of L2 and 16 native Mandarin Chinese listeners as late learners of L2 rated hyperarticulated samples versus non-hyperarticulated samples for comprehension under four listening conditions of varying white noise level (quiet or SNR levels of +16dB, +12dB or +8dB). from (3x2x4 mixed design). Mean ratings showed all three groups found hyperarticulated speech samples easier to understand than non-hyperarticulated speech at all listening conditions. Results are discussed in terms of other findings (Uther et al., 2012) that suggest that hyperarticulation may generally improve speech processing for all language groups.

Bradlow, A. R., and Bent, T. (2002). The clear speech effect for non-native listeners. Journal of the Acoustical Society of America. 112 (1), 272-284.

Bradlow, A. R., Kraus, N., and Erin, H. �(2003)�. Speaking clearly for learning-impaired children: Sentence perception in noise, Journal of Speech Language Hearing Research (46), 80–97.

Hustad, K. C. (2008). The relationship between listener comprehension and intelligibility scores for speakers with dysarthria. Journal of Speech Language Hearing Research, 51(3), 562–573.

Hustad KC, Beukelman DR. (2002) Listener comprehension of severely dysarthric speech: effects of linguistic cues and stimulus cohesion. Journal of Speech, Language, and Hearing Research. (45) 545–558.

Uther, M., Giannakopoulou, A. & Iverson, P. (2012) Hyperarticulation of vowels enhances phonetic change responses in both native and non-native speakers of English: evidence from an auditory event-related potential study. Brain Research, (1470), 52-8.

Acknowledgements: This work was supported by an Isambard Scholarship from Brunel University