Bilingualism and Speech Understanding in Noise: Auditory and Linguistic Factors

Abstract

Bilingual speakers often have difficulty understanding speech in noisy and acoustically degraded conditions.The first aim was to examine the potential source(s) of the difficulties that English-proficient bilingual listeners experience when hearing English speech in noise. The second aim was to assess how bilingual listeners perform on a battery of central auditory processing tests.A mixed design was used in this study.Normal-hearing college students (n = 24) participated in this study. The bilingual participants (n = 12) self-reported that they learned a second language before age 9 and the monolingual participants reported that they only knew American English. All participants considered themselves to be native speakers of American English.Participants were administered the Revised Speech Perception in Noise (R-SPIN) test to assess whether bilingual listeners’ speech understanding in noise reflects auditory factors, linguistic factors, or a combination of the two. To minimize the influence of short-term memory and motor movements, only the final word of a sentence is repeated for this test. Sentence-final words were presented in two linguistic contexts: in the high-predictability condition, the final word can be deduced from the context created by the preceding words, and in the low-predictability condition, it cannot. The R-SPIN test was administered at two signal-to-noise ratios (SNRs) (0 and 3 dB). In addition, the participants were given a reading comprehension test to measure their ability to use context when linguistic stimuli are delivered to the visual, not auditory, modality. The central auditory test battery consisted of three tests: Competing Sentences, Dichotic Digits, and NU-6 Time-Compressed Speech with Reverberation. All test materials were given in American English.The bilingual and monolingual groups performed similarly in the low-context condition of the R-SPIN test. However, in comparison to the age-matched monolingual group, the bilingual group did not derive the same level of benefit from contextual cues, as seen by a smaller improvement in performance between the low- and high-predictability R-SPIN conditions. The bilingual and monolingual groups showed a similar decrement in performance when the SNR dropped. In addition, bilingual individuals underperformed on the Competing Sentences test when instructed to attend to the left ear. However, the bilingual and monolingual groups performed equally well on the reading comprehension test, as well as on the Time-Compressed Speech with Reverberation and Dichotic Digits tests.We show that individuals who are exposed to two languages from an early age, and self-report as having a high level of proficiency in English, perform like their monolingual counterparts in acoustically degraded conditions where context is not facilitative, but they underperform in conditions where sentence-level linguistic context is facilitative to understanding. We conclude that deficits observed in noise are likely not due to a perceptual deficit or a lack of linguistic competence, but instead reflect a linguistic system that performs inefficiently in noise. In addition, we do not find evidence of an auditory processing weakness or advantage in our bilingual cohort; however, the use of speech materials to assess auditory processing is a confound.

Bilinguals’ speech perception in noise: Perceptual and neural associations

“…Instead of relying on one type of speech stimulus, we included two types to reflect the perception of the individual. This was done because previous studies have shown that bilinguals show more difficulty in noise as the linguistic complexity of the task increases [ 7 , 17 , 61 – 67 ]. Here, to evaluate the relation between physiology and perceptual measures, we combined the perceptual accuracy of the individual in both wordlists and sentences to reflect the perceptual performance in general, regardless of the effect of task complexity on performance.…”

“…One challenging listening condition that deteriorates speech perception is background noise [ 1 – 3 ]. It is well-known that speech perception in the presence of background noise can be more challenging for bilinguals compared to monolinguals [ 4 – 16 ] and that this disadvantage is present even when bilinguals have early exposure and strong proficiency in both languages [ 7 , 16 , 17 ]. At the same time, the literature notes the advantages of bilingualism for brain structure and function (e.g., [ 18 , 19 ]).…”

Listening in the Moment: How Bilingualism Interacts With Task Demands to Shape Active Listening

“…Bilinguals previously were shown to have enhanced inhibitory control (Bialystok, 2011(Bialystok, , 2015 and subcortical encoding of the F0 of speech (Krizman et al, 2012;Skoe et al, 2017), processes that are fundamental to understanding speech in noise. Despite these advantages, bilinguals perform more poorly on clinical tests of speech-in-noise recognition (Shi, 2010(Shi, , 2012Lucks Mendel and Widner, 2016;Krizman et al, 2017;Skoe and Karayanidi, 2019). In this study, by assessing bilinguals and monolinguals on a selective attention task, a type of speechin-noise task that calls upon auditory processing and executive control, we could determine whether bilingual cognitive and sensory enhancements have benefits for everyday listening situations.…”

“…Previous literature, however, has found bilinguals struggle in this realm relative to monolinguals (Mayo et al, 1997;Cooke et al, 2008;Lecumberri et al, 2011;Lucks Mendel and Widner, 2016;Krizman et al, 2017;Morini, 2020). Despite bilinguals' cognitive and sensory enhancements, they perform more poorly than monolinguals on clinical assessments of listening to speech in noise (Shi, 2010(Shi, , 2012Stuart et al, 2010;Krizman et al, 2017;Skoe and Karayanidi, 2019). Interestingly, this perception-innoise disadvantage only manifests when the target is linguistic; bilinguals instead show an advantage when the target is nonlinguistic (i.e., a tone; Krizman et al, 2017).…”

R2SPIN: Re-Recording the Revised Speech Perception in Noise Test

“…Whilst highly valuable research tools, these tests require substantial time and resource to develop and validate. For this reason a single test, once developed, is often utilized for many decades [1,12]. This facilitates comparison of current results to previous research and the normative values for the original test [13].…”