Speech Intelligibility Benefit Research Articles

Is there an interlanguage speech credibility benefit?

Abstract Some (though not all) previous studies have documented the interlanguage speech intelligibility benefit (ISIB), i.e. the greater intelligibility of non-native (relative to native) speech to non-native listeners as compared to native listeners. Moreover, some studies (again not all) found that native listeners consider foreign-accented statements as less truthful than native-sounding ones. We join these two lines of research, asking whether foreign-accented statements sound more credible to non-native than to native listeners and whether difficult-to-process (less comprehensible) utterances are less credible. In two experiments we measure the intelligibility, comprehensibility and credibility of native and foreign-accented statements for native listeners and non-native listeners matched or mismatched in L1 with non-native talkers. We find an ISIB in both matched and mismatched non-native listeners, and an analogous matched comprehensibility benefit. However, we obtain no evidence of an interlanguage speech credibility benefit. Instead, both matched and mismatched non-native listeners tend to trust native statements more (i.e. statements produced by their target-language models). For native listeners, we do not confirm the tendency to mistrust non-native statements, but we do find a moderate correlation between the comprehensibility and credibility of foreign-accented utterances, giving limited support to the hypothesis that decreased perceptual fluency leads to decreased credibility.

Production and perception of clear speech

When talkers are aware of listeners’ speech perception difficulties due to hearing loss, noise, or a language barrier, they typically adopt an intelligibility-enhancing speaking style known as “clear speech.” To the extent that clear speech is more intelligible than “conversational speech,” a cross-style acoustic-phonetic comparison provides information about factors that affect speech intelligibility. I will present data from a project that tested the hypothesis that clear speech is guided by both universal, auditory-perceptual factors and language-specific, structural factors. The former serve to enhance the overall acoustic salience of the speech signal such that it is more resistant to the adverse effects of noise or listener-related perceptual deficits; the latter serves to enhance the realization of phonological contrasts. This hypothesis predicts that clear speech production shows predictable and systematic cross-language similarities and differences, and that the clear speech intelligibility benefit is modulated by the listeners’ experience with the target language. To address these predictions, we present data from a cross-language comparison of clear speech production and a cross-population comparison of clear speech perception. These studies provide fundamental information about variability in speech intelligibility which may ultimately lead to effective, efficient, and listener-specific speech intelligibility enhancement strategies.

On Detectable and Meaningful Speech-Intelligibility Benefits.

The most important parameter that affects the ability to hear and understand speech in the presence of background noise is the signal-to-noise ratio (SNR). Despite decades of research in speech intelligibility, it is not currently known how much improvement in SNR is needed to provide a meaningful benefit to someone. We propose that the underlying psychophysical basis to a meaningful benefit should be the just noticeable difference (JND) for SNR. The SNR JND was measured in a series of experiments using both adaptive and fixed-level procedures across participants of varying hearing ability. The results showed an average SNR JND of approximately 3 dB for sentences in same-spectrum noise. The role of the stimulus and link to intelligibility was examined by measuring speech-intelligibility psychometric functions and comparing the intelligibility JND estimated from those functions with measured SNR JNDs. Several experiments were then conducted to establish a just meaningful difference (JMD) for SNR. SNR changes that could induce intervention-seeking behaviour for an individual were measured with subjective scaling and report, using the same stimuli as the SNR JND experiment as pre- and post-benefit examples. The results across different rating and willingness-to-change tasks showed that the mean ratings increased near linearly with a change in SNR, but a change of at least 6 dB was necessary to reliably motivate participants to seek intervention. The magnitude of the JNDs and JMDs for speech-intelligibility benefits measured here suggest a gap between what is achievable and what is meaningful.

The Interlanguage Speech Intelligibility Benefit as Bias Toward Native-Language Phonology.

Two hypotheses have been advanced in the recent literature with respect to the so-called Interlanguage Speech Intelligibility Benefit (ISIB): a nonnative speaker will be better understood by a another nonnative listener than a native speaker of the target language will be (a) only when the nonnatives share the same native language (matched interlanguage) or (b) even when the nonnatives have different mother tongues (non-matched interlanguage). Based on a survey of published experimental materials, the present article will demonstrate that both the restricted (a) and the generalized (b) hypotheses are false when the ISIB effect is evaluated in terms of absolute intelligibility scores. We will then propose a simple way to compute a relative measure for the ISIB (R-ISIB), which we claim is a more insightful way of evaluating the interlanguage benefit, and test the hypotheses in relative (R-ISIB) terms on the same literature data. We then find that our R-ISIB measure only supports the more restricted hypothesis (a) while rejecting the more general hypothesis (b). This finding shows that the native language shared by the interactants biases the listener toward interpreting sounds in terms of the phonology of the shared mother tongue.

Effects of listener factors and stimulus properties on the intelligibility, comprehensibility and accentedness of L2 speech

The intelligibility, comprehensibility and foreign accentedness of native and Polish-accented English sentences were evaluated by six Polish, six Spanish and six English speakers. The nonnative data were also analyzed for segmental and word stress errors. Results indicated that the three measures were partially independent of one another, supporting earlier findings that accented speech can be intelligible and comprehensible. An interlanguage speech intelligibility detriment was observed for Spanish listeners, but no clear evidence of an interlanguage speech intelligibility benefit was found, as nonnative listeners never outperformed native listeners. The number of segmental errors, rather than lexical stress errors, was found to correlate with comprehensibility and accentedness ratings of nonnative speech, but not with intelligibility scores. In general, the results point to a greater effect of stimulus properties than of listeners’ L1s in the perception of nonnative speech.

Speech intelligibility benefits of hearing AIDS at various input levels.

Although the benefits of hearing aids are generally recognized for soft- and conversational-level sounds, most studies have reported negative benefits (i.e., poorer aided than unaided performance) at high noise inputs. Advances in digital signal processing such as compression, noise reduction, and directional microphone could improve speech perception at high input levels. This could alter our view on the efficacy of hearing aids in loud, noisy situations. The current study compared the aided versus the unaided speech intelligibility performance of hearing-impaired (HI) listeners at various input levels (from 50-100 dB SPL) and signal-to-noise ratios (SNRs; quiet, +6, +3, and -3 dB) in order to document the benefits of modern hearing aids. In addition, subjective preference between aided and unaided sounds (speech and music) at various input levels was also compared. The experiment used a factorial repeated-measures design. A total of 10 HI adults with symmetrical moderate to severe hearing losses served as test participants. In addition, speech intelligibility scores of five normal-hearing (NH) listeners were also measured for comparison. Speech perception was studied at 50 and 65 dB SPL input levels in quiet and also in noise at levels of 65, 85, and 100 dB SPL with SNRs of +6, +3, and -3 dB. This was done for all participants (HI and NH). In addition, the HI participants compared subjective preference between the aided and unaided presentations of speech and music stimuli at 50, 65, 85, and 100 dB SPL in quiet. The data were analyzed with repeated-measures analysis of variance. The results showed a decrease in aided benefits as input levels increased. However, even at the two highest input levels (i.e., 85 and 100 dB SPL), aided speech scores were still higher than the unaided speech scores. Furthermore, NH listeners and HI listeners in the aided condition showed stable speech-in-noise performance between 65 and 100 dB SPL input levels, except that the absolute performance of the NH listeners was higher than that of the HI listeners. Subjective preference for the unaided sounds versus the aided sounds increased as input level increased, with a crossover intensity at approximately 75 dB SPL for speech and 80 dB SPL for music. The results supported the hypothesis that the study hearing aid can provide aided speech-in-noise benefit at very high noise inputs in a controlled environment.

Audio-visual speech intelligibility benefits with bilateral cochlear implants when talker location varies.

One of the key benefits of using cochlear implants (CIs) in both ears rather than just one is improved localization. It is likely that in complex listening scenes, improved localization allows bilateral CI users to orient toward talkers to improve signal-to-noise ratios and gain access to visual cues, but to date, that conjecture has not been tested. To obtain an objective measure of that benefit, seven bilateral CI users were assessed for both auditory-only and audio-visual speech intelligibility in noise using a novel dynamic spatial audio-visual test paradigm. For each trial conducted in spatially distributed noise, first, an auditory-only cueing phrase that was spoken by one of four talkers was selected and presented from one of four locations. Shortly afterward, a target sentence was presented that was either audio-visual or, in another test configuration, audio-only and was spoken by the same talker and from the same location as the cueing phrase. During the target presentation, visual distractors were added at other spatial locations. Results showed that in terms of speech reception thresholds (SRTs), the average improvement for bilateral listening over the better performing ear alone was 9 dB for the audio-visual mode, and 3 dB for audition-alone. Comparison of bilateral performance for audio-visual and audition-alone showed that inclusion of visual cues led to an average SRT improvement of 5 dB. For unilateral device use, no such benefit arose, presumably due to the greatly reduced ability to localize the target talker to acquire visual information. The bilateral CI speech intelligibility advantage over the better ear in the present study is much larger than that previously reported for static talker locations and indicates greater everyday speech benefits and improved cost-benefit than estimated to date.

Measurements of monopolar and bipolar current spreads using forward-masking with a fixed probe

ObjectivesThis research employed a forward-masking paradigm to estimate the current spread of monopolar (MP) and bipolar (BP) maskers, with current amplitudes adjusted to elicit the same loudness. Since the spatial separation between active and return electrodes is smaller in BP than in MP configurations, the BP current spread is more localized and presumably superior in terms of speech intelligibility. Because matching the loudness requires higher current in BP than in MP stimulation, previous forward-masking studies show that BP current spread is not consistently narrower across subjects or electrodes within a subject.MethodsThe present forward-masking measures of current spread differ from those of previous studies by using the same BP probe electrode configuration for both MP and BP masker configurations, and adjusting the current levels of the MP and BP maskers so as to match them in loudness. With this method, the estimate of masker current spread would not be contaminated by differences in probe current spread. Forward masking was studied in four cochlear implant patients, two females and two males, with speech recognition scores higher than 50%; that is, their auditory-nerve survival status was more than adequate to carry out the experiments.ResultsThe data showed that MP and BP masker configurations produce equivalent masking patterns (and current spreads) in three participants. A fourth participant displayed asymmetrical patterns with enhancement rather than masking in some cases, especially when the probe and masker were at the same location.DiscussionThis study showed equivalent masking patterns for MP and BP maskers when the BP masker current amplitude was increased to match the loudness of the MP masker, and the same BP probe configuration is used with both maskers. This finding could help to explain why cochlear implant users often fail to accrue higher speech intelligibility benefit from BP stimulation.

The contribution of durational and spectral changes to the Lombard speech intelligibility benefit.

Speech produced in the presence of noise (Lombard speech) is typically more intelligible than speech produced in quiet (plain speech) when presented at the same signal-to-noise ratio, but the factors responsible for the Lombard intelligibility benefit remain poorly understood. Previous studies have demonstrated a clear effect of spectral differences between the two speech styles and a lack of effect of fundamental frequency differences. The current study investigates a possible role for durational differences alongside spectral changes. Listeners identified keywords in sentences manipulated to possess either durational or spectral characteristics of plain or Lombard speech. Durational modifications were produced using linear or nonlinear time warping, while spectral changes were applied at the global utterance level or to individual time frames. Modifications were made to both plain and Lombard speech. No beneficial effects of durational increases were observed in any condition. Lombard sentences spoken at a speech rate substantially slower than their plain counterparts also failed to reveal a durational benefit. Spectral changes to plain speech resulted in large intelligibility gains, although not to the level of Lombard speech. These outcomes suggest that the durational increases seen in Lombard speech have little or no role in the Lombard intelligibility benefit.

Listening with a foreign-accent: The interlanguage speech intelligibility benefit in Mandarin speakers of English

This study examined the intelligibility of native and Mandarin-accented English speech for native English and native Mandarin listeners. In the latter group, it also examined the role of the language environment and English proficiency. Three groups of listeners were tested: native English listeners (NE), Mandarin-speaking Chinese listeners in the US (M-US) and Mandarin listeners in Beijing, China (M-BJ). As a group, M-US and M-BJ listeners were matched on English proficiency and age of acquisition. A nonword transcription task was used. Identification accuracy for word-final stops in the nonwords established two independent interlanguage intelligibility effects. An interlanguage speech intelligibility benefit for listeners (ISIB-L) was manifest by both groups of Mandarin listeners outperforming native English listeners in identification of Mandarin-accented speech. In the benefit for talkers (ISIB-T), only M-BJ listeners were more accurate identifying Mandarin-accented speech than native English speech. Thus, both Mandarin groups demonstrated an ISIB-L while only the M-BJ group overall demonstrated an ISIB-T. The English proficiency of listeners was found to modulate the magnitude of the ISIB-T in both groups. Regression analyses also suggested that the listener groups differ in their use of acoustic information to identify voicing in stop consonants.

Intelligibility of Clear Speech: Effect of Instruction

The authors investigated how clear speech instructions influence sentence intelligibility. Twelve speakers produced sentences in habitual, clear, hearing impaired, and overenunciate conditions. Stimuli were amplitude normalized and mixed with multitalker babble for orthographic transcription by 40 listeners. The main analysis investigated percentage-correct intelligibility scores as a function of the 4 conditions and speaker sex. Additional analyses included listener response variability, individual speaker trends, and an alternate intelligibility measure: proportion of content words correct. Relative to the habitual condition, the overenunciate condition was associated with the greatest intelligibility benefit, followed by the hearing impaired and clear conditions. Ten speakers followed this trend. The results indicated different patterns of clear speech benefit for male and female speakers. Greater listener variability was observed for speakers with inherently low habitual intelligibility compared to speakers with inherently high habitual intelligibility. Stable proportions of content words were observed across conditions. Clear speech instructions affected the magnitude of the intelligibility benefit. The instruction to overenunciate may be most effective in clear speech training programs. The findings may help explain the range of clear speech intelligibility benefit previously reported. Listener variability analyses suggested the importance of obtaining multiple listener judgments of intelligibility, especially for speakers with inherently low habitual intelligibility.

The matched and mismatched interlanguage speech intelligibility benefit for listeners (ISIB-L): Chinese L2 talkers’ production of English liquids

The matched and mismatched interlanguage speech intelligibility benefit for listeners (ISIB-L): Chinese L2 talkers’ production of English liquids

The Interlanguage Speech Intelligibility Benefit (ISIB) of English Prosody: The Case of Focal Prominence for Korean Learners of English and Natives

This study investigated the speech intelligibility of Korean-accented and native English focus speech for Korean and native English listeners. Three different types of focus in English, broad, narrow and contrastive, were naturally induced in semantically optimal dialogues. Seven high and seven low proficiency Korean speakers and seven native speakers participated in recording the stimuli with another native speaker. Fifteen listeners from each of Korean high & low proficiency and native groups judged audio signals of focus sentences. Results showed that Korean listeners were more accurate at identifying the focal prominence for Korean speakers' narrow focus speech than that of native speakers, and this suggests that the interlanguage speech intelligibility benefit-talker (ISIB-T) held true for narrow focus regardless of Korean speakers' and listeners' proficiency. However, Korean listeners did not outperform native listeners for Korean speakers' production of narrow focus, which did not support for the ISIB-listener (L). Broad and contrastive focus speech did not provide evidence for either the ISIB-T or ISIB-L. These findings are explained by the interlanguage shared by Korean speakers and listeners where they have established more L1-like common phonetic features and phonological representations. Once semantically and syntactically interpreted in a higher level processing in Korean narrow focus speech, the narrow focus was phonetically realized in a more intelligible way to Korean listeners due to the interlanguage. This may elicit ISIB. However, Korean speakers did not appear to make complete semantic/syntactic access to either broad or contrastive focus, which might lead to detrimental effects on lower level phonetic outputs in top-down processing. This is, therefore, attributed to the fact that Korean listeners did not take advantage over native listeners for Korean talkers and vice versa.

The role of first-language production accuracy and talker-listener alignment in second-language speech Intelligibility

This study investigated variability in L2 speech intelligibility as a function of L1 speech intelligibility and of talker-listener L1 match. Non-native Korean talkers varying in their L2 proficiency were recorded reading simple English (L2) and Korean (L1) sentences. The intelligibility of these sentences was then assessed by Korean listeners (both Korean and English productions) and English listeners (English productions only) in a sentence recognition task. The results revealed that for these Korean-English bilingual talkers, L1 intelligibility was significantly correlated with L2 intelligibility for both Korean and English listeners, suggesting that variability in L1 speech intelligibility can serve as a predictor of variability in L2 production accuracy. We also examined the interlanguage speech intelligibility benefit for non-native listeners (ISIB-L) (e.g., Bent & Bradlow, 2003; Hayes-Harb et al., 2008). Korean listeners performed better at identifying the sentences produced by Korean talkers with relatively low L2 intelligibility, implying that the benefit of a shared native language between talkers and listeners may be larger when non-native listeners process speech from a talker with low L2 intelligibility. Overall, these findings indicate that variability in L2 speech intelligibility is related to language-general talker characteristics as well as to the talker-listener language alignment.

Acoustic correlates of vowel intelligibility in clear and conversational speech for young normal-hearing and elderly hearing-impaired listeners

Previous reports on the relationship between clear speech acoustic changes and the clear speech intelligibility benefit for vowels have used an “extreme groups” design, comparing talkers who produced a large clear speech benefit to talkers who produced little or no clear speech benefit. In Ferguson and Kewley-Port (2007), 12 talkers from the Ferguson Clear Speech Database (Ferguson, 2004) were assigned to groups based on the vowel identification performance of young normal-hearing listeners, while Ferguson (2010) chose 20 talkers based on the performance of elderly hearing-impaired listeners. The present investigation is employing mixed-effects models to examine relationships among acoustic and perceptual data obtained for vowels produced by all 41 talkers of the Ferguson database. Acoustic data for the 1640 vowel tokens (41 talkers X 10 vowels X 2 tokens X two speaking styles) include vowel duration, vowel space, and several different measures of dynamic formant movement. Perceptual data consist of vowel intelligibility in noise as reflected by the performance of young normal-hearing and elderly hearing-impaired listeners. Analyses will explore the relative importance of the various clear speech acoustic changes to the clear speech vowel intelligibility effect as well as the degree to which this relationship varies between the two listener groups.

Noise reduction for auditory prostheses based on harmonic detection

Difficulty in understanding speech in background noise is one of the most common complaints of hearing-aid and cochlear-implant users. Various noise-reduction and spectral-enhancement algorithms have been designed and tested over the years, often with limited success in terms of improving speech intelligibility. A commonly used method involves spectral subtraction, which is based on the assumption that the noise spectrum can be estimated and the clean speech signal can be extracted by subtracting the noise spectrum from the noisy speech signal. However, recent studies have shown that such methods often result in poorer signal-to-noise ratios in the modulation-spectrum domain, which may explain why little benefit in speech intelligibility has been found. Also, identifying noise in terms of its stationarity runs the risk of misidentification in more stationary signals, such as music. Here a noise reduction algorithm based on harmonic detection and enhancement was explored. Simulation results showed that this algorithm could help suppress noise in both speech and music. Results from perceptual tests will be reported. [Supported in part by Advanced Bionics.]

The speech intelligibility benefit of a unilateral wireless system for hearing-impaired adults

Objective: This study measured the effects of two previously untested practical considerations—venting and transmission delays—on speech intelligibility in a simulated unilateral wireless system, where a target signal in background noise was transmitted wirelessly to the hearing-impaired (HI) listener. Design: Speech reception thresholds (SRTs) relative to the signal-to-noise ratio (SNR) were measured by varying the surrounding babble noise level. The target signal was presented at 0° azimuth in the soundfield and unilaterally via an insert earphone, using open and closed fittings with simulated-wireless delays ranging between 0–160 ms. SRTs were also measured unaided and with participants’ current hearing aid(s). Study sample: Thirty-three mild-to-moderate sensorineural HI adults participated in the experiment. Results: For an open fitting, the results showed a 5-dB SNR benefit in SRT compared to unaided performance at shorter delays. For a closed fitting, the majority of participants could accurately recognize speech below − 20 dBSNR across delays. Conclusions: These results highlight the efficacy of wireless systems with HI adults. Speech-intelligibility benefits are affected by transmission delays only when the delay is greater than 40 ms and the coupling is vented.SumarioObjetivo: Este estudio midió los efectos de dos condiciones prácticas que no han sido probadas con anterioridad – ventilación y retardos en la transmisión – sobre la inteligibilidad del lenguaje en un sistema unilateral inalámbrico simulado, en el que la señal objetivo en ambiente ruidoso fue transmitida en forma inalámbrica a la persona con hipoacusia (HI). Results: Diseño: Los umbrales de recepción del habla (SRT) relativos al ratio señal/ruido (SNR) fueron medidos variando el nivel de ruidobalbuceante circ undante. La señal objetivo fue presentada a 0° azimut en el campo libre y por medio de un audífono de inserción, utilizando adaptaciones abiertas y cerradas con retardo simulado inalámbrico entre 0 y 160 ms. Los SRT también fueron medidos sin auxiliar y con los auxiliares propios de los participantes. Muestra: Treinta y tres adultos con hipoacusia sensorineural leve a moderada participaron en el experimento. Resultados: Cuando se utiliz la adaptación abierta, los resultados mostraron un beneficio de 5dB en el SRT comparado con el desempe o sin auxiliar con un retardo más corto. Con la adaptación cerrada, la mayoría de los participantes pudieron reconocer acertadamente el lenguaje a − 20 dB SNR en todas las condiciones de retraso. Conclusiones: Estos resultados resaltan la eficacia de los sistemas inalámbricos para los adultos con hipoacusia. Los beneficios en la inteligibilidad del lenguaje son afectados por los retrasos en la transmisión, sólo cuando el retraso es mayor a 40 ms y el molde tiene ventilación.

The Interlanguage Speech Intelligibility Benefit for Korean Learners of English: Perception of English Front Vowels

ABSTRACTThe present work is a follow-up study to that of Han, Choi, Lim and Lee (2011), where an asymmetry in the source segments eliciting the interlanguage speech intelligibility benefit (ISIB) was found such that the vowels which did not match any vowel of the Korean language were likely to elicit more ISIB than matched vowels. In order to identify the source of the stronger ISIB in non-matched vowels, acoustic analyses of the stimuli were performed. Two pairs of English front vowels [i] vs. [ɪ], and [ɛ] vs. [ae] were recorded by English native talkers and two groups of Korean learners according to their English proficiency, and then their vowel duration and the frequencies of the first two formants (F1, F2) were measured. The results demonstrated that the non-matched vowels such as [ɪ], and [ae] produced by Korean talkers seemed to show more deviated acoustic characteristics from those of the natives, with longer duration and with closer formant values to the matched vowels, [i] and [ɛ], than those of the English natives. Combining the results of acoustic measurements in the present study and those of word identification in Han et al. (2011), we suggest that relatively better performance in word identification by Korean talkers/listeners than the native English talkers/listeners is associated with the shared interlanguage of Korean talkers and listeners. Key words: the interlanguage speech intelligibility benefit (ISIB), Korean front vowels

Discrimination of stochastic frequency modulation as a predictor of electro-acoustic stimulation benefit.

The amount of benefit in speech intelligibility in noise can vary widely for cochlear-implant (CI) users when low-frequency acoustic stimulation is combined with electric stimulation. This variability may, in part, be explained by the listener’s ability to follow fundamental frequency (f0) changes with electric stimulation only: those who benefit the least may be most adept at processing f0 in the electric region. The present study measured the ability of CI users to discriminate stochastic FM patterns when presented acoustically or electrically only. The stimuli were 200-Hz carriers randomly modulated in frequency by 5-Hz lowpass noise. A cued 2IFC procedure was used. In one of the two observation intervals, the cue pattern was repeated; in the other, the modulator was inverted so that the pattern of instantaneous frequency fluctuation mirrored that of the cue pattern at the center frequency. Discrimination thresholds were measured in terms of the FM depth needed to discriminate the deviant from the cue pattern. Additional conditions disrupted FM-to-AM conversion by adding extraneous AM to either the carrier or a noise masker. The discrimination results will be compared to the benefit in speech intelligibility obtained by CI users when presented with low-frequency acoustic cues. [Work supported by NIDCD.]

The interlanguage speech intelligibility benefit-listeners for Chinese accented English liquids.

This study investigated the intelligibility of Chinese-accented English liquids for native English, Chinese, and Korean listeners. The lateral /l/ and the retroflex /r/ in syllable initial and final positions were examined in three different contexts: segment, word, and sentence. Three groups of listeners with different language backgrounds accomplished a forced-choice identification task. For Chinese talkers’ production of the English liquids, both matched and mismatched interlanguage speech intelligibility benefits for listeners (ISIB-L) occurred in all the four positions except for the initial /l/ produced by low proficiency Chinese talkers. The ISIB-L, however, held only for high proficiency non-native listeners. The only exception was the syllable initial /l/ stimuli produced by low proficiency Chinese talkers in such a way that native English listeners were more accurate than Chinese and Korean listeners at identifying the strong Chinese accented syllable initial /l/ sound. Considering the contextual effects on ISIB-L, matched ISIB-L only occurred for high proficiency listeners in the segment context. There was evidence of both matched and mismatched ISIB-L effects only for high proficiency listeners in word context. In the sentence context, English listeners performed better than all non-native listeners; therefore, there was no evidence for ISIB-L.