Non-native speech perception in adverse conditions: A review <s> Non-native speech perception under energetic masking <s> In this study, the effect of linguistic experience on the auditory discrimination of words has been examined. 18 subjects, including 6 native and 12 non-native speakers of English, were tested with CID auditory test W-22 in quiet and in the presence of white noise at the signal-to-noise (S/N) ratios of + 12, + 6 and 0 dB. The non-native speakers of English included 6 with 1 year of experience and 6 with 3–4 years of experience speaking English in the USA.In the absence of noise, the results were essentially equivalent for all three groups. As noise level increased, word discrimination deteriorated for all three groups with non-native speakers of English obtaining results significantly poorer than native speakers of English. Linguistic experience and noise levels were significant at the 0.001 level of confidence. It appears that at 0 dB S/N, individual variability of non-native speakers of English, regardless of their original linguistic background, was much smaller than that found for native speakers of E... <s> BIB001 </s> Non-native speech perception in adverse conditions: A review <s> Non-native speech perception under energetic masking <s> The noise level at which native and non‐native listeners could repeat about 50% of very simple English sentences was measured with an adaptive procedure. The 14 non‐native listeners were primarily native French speaking and were 19 to 53 years old. Four native listeners were 16 to 53 years old. On each trial the listener repeated one sentence presented at 70 dB SPL via loudspeakers in an anechoic chamber. If the entire sentence was correct, the noise level was increased; otherwise it was decreased. the step size was 5 dB until the first reversal and 2 dB thereafter. The speech reception threshold, SRT, was defined as the average noise level of ten trials following the first reversal. Three SRTs were measured for each listener. All listeners could repeat eight practice sentences presented in the quiet with 100% accuracy. The average SRTs were 57 dB SPL for listeners with minimal experience in English, 62 dB SPL for listeners with moderate experience, and 68 dB SPL for listeners with extensive experience. N... <s> BIB002 </s> Non-native speech perception in adverse conditions: A review <s> Non-native speech perception under energetic masking <s> To determine how age of acquisition influences perception of second-language speech, the Speech Perception in Noise (SPIN) test was administered to native Mexican-Spanish-speaking listeners who lea... <s> BIB003 </s> Non-native speech perception in adverse conditions: A review <s> Non-native speech perception under energetic masking <s> This study examined the recognition of English words by groups of native speakers of Italian who differed in age of arrival in Canada and amount of continued native language use. The dependent variable was the number of words correctly repeated in English sentences presented in noise. Significantly higher word recognition scores were obtained for early than late bilinguals, and for early bilinguals who used Italian seldom than for early bilinguals who used Italian relatively often. A hierarchical regression analysis showed that the native Italian participants' ability to perceive English vowels and consonants accounted for a significant amount of variance in the word-recognition scores independently of age of arrival, amount of L1 use, and length of residence in Canada. The native language use effect was interpreted to have arisen from differences in the extent to which the early bilinguals' Italian phonetic system influenced the representations they developed for English vowels and consonants. <s> BIB004 </s> Non-native speech perception in adverse conditions: A review <s> Non-native speech perception under energetic masking <s> Previous research has suggested that child but not adult immigrants to the United States and ::: Canada make regular progress learning English as their length of residence (LOR) increases. If ::: children and adults received the same kind of second language (L2) input, such evidence would ::: support the existence of a critical period for L2 acquisition. The present study compared groups ::: of Chinese adults living in the United States who differed in LOR in order to assess the role of ::: input in adults' naturalistic acquisition of an L2. We assessed the Chinese ::: participants' identification of word-final English consonants (experiment 1), their scores on ::: a 144-item grammaticality judgment test (experiment 2), and their scores on a 45-item listening ::: comprehension test (experiment 3). The Chinese participants were assigned to one of four groups ::: ( n = 15 each) based on LOR in the United States and their primary occupation ::: (students vs. nonstudents). Significantly higher scores were obtained for the students with ::: relatively long LORs than for the students with relatively short LORs in all three experiments. ::: However, the difference between the nonstudents differing in LOR was nonsignificant in each ::: instance. The results suggested that the lack of an effect of LOR in some previous studies may ::: have been due to sampling error. It appears that adults' performance in an L2 will improve ::: measurably over time, but only if they receive a substantial amount of native speaker input. <s> BIB005 </s> Non-native speech perception in adverse conditions: A review <s> Non-native speech perception under energetic masking <s> Abstract Objectives: To avoid the accidents induced by confusions of non-native speech perception in the presence of noise at work, this study examined the effect of background noise on the discrimination of English speech for Japanese listeners. Methods: Normal hearing Japanese subjects, who have English learning experience to the level of college graduates, were tested with the CID W-22 word list in quiet settings and in the presence of white, low-frequency weighted (pink noise), or aircraft noise. Results: The discrimination scores were reduced as S/N ratio decreased, and more adversely affected by background white noise than pink or aircraft noise. The individual variability of English word discrimination scores for Japanese listeners was much larger as the S/N ratio decreased. The typical confusions among phoneme were /m/, /n/, and /s/. Conclusions: The results of this study suggested that ineffective use of speech cues and difference in composition of English phonemes from Japanese could be responsible for degraded speech discrimination of non-native speech in noise. Moreover, it was expected that Japanese workers with age related hearing loss at higher frequencies might have great difficulty in perceiving English speech sounds in the presence of noise. <s> BIB006 </s> Non-native speech perception in adverse conditions: A review <s> Non-native speech perception under energetic masking <s> When listening to languages learned at a later age, speech intelligibility is generally lower than when listening to one's native language. The main purpose of this study is to quantify speech intelligibility in noise for specific populations of non-native listeners, only broadly addressing the underlying perceptual and linguistic processing. An easy method is sought to extend these quantitative findings to other listener populations. Dutch subjects listening to Germans and English speech, ranging from reasonable to excellent proficiency in these languages, were found to require a 1-7 dB better speech-to-noise ratio to obtain 50% sentence intelligibility than native listeners. Also, the psychometric function for sentence recognition in noise was found to be shallower for non-native than for native listeners (worst-case slope around the 50% point of 7.5%/dB, compared to 12.6%/dB for native listeners). Differences between native and non-native speech intelligibility are largely predicted by linguistic entropy estimates as derived from a letter guessing task. Less effective use of context effects (especially semantic redundancy) explains the reduced speech intelligibility for non-native listeners. While measuring speech intelligibility for many different populations of listeners (languages, linguistic experience) may be prohibitively time consuming, obtaining predictions of non-native intelligibility from linguistic entropy may help to extend the results of this study to other listener populations. <s> BIB007 </s> Non-native speech perception in adverse conditions: A review <s> Non-native speech perception under energetic masking <s> Recent evidence on the perceptual performance of bilingual listeners suggests that a nonaudibility-based cost exists in processing a second language. That is, when compared to monolingual English speakers and early bilinguals, listeners who acquired English as a second language after puberty show reduced performance when listening to the second language in background noise, despite normal auditory thresholds. However, past studies have not controlled for the homogeneity of the bilingual participants used in auditory research; therefore, it is unknown whether the deficit observed in bilingual function is due to a lack of control for language-related variables. The ability of a homogeneous group of Spanish-English bilinguals and English monolingual listeners to perceive sentences in quiet and in noise at threshold levels was evaluated using the Hearing in Noise Test (HINT). Both groups performed similarly in quiet conditions. In the noise conditions, the bilingual group's performance was significantly poorer than the monolingual group's performance. However, both groups showed a binaural advantage of 7-8 dB when the signal and noise were separated by 90 degrees. <s> BIB008 </s> Non-native speech perception in adverse conditions: A review <s> Non-native speech perception under energetic masking <s> Native American English and non-native (Dutch) listeners identified either the consonant or the vowel in all possible American English CV and VC syllables. The syllables were embedded in multispeaker babble at three signal-to-noise ratios (0, 8, and 16 dB). The phoneme identification performance of the non-native listeners was less accurate than that of the native listeners. All listeners were adversely affected by noise. With these isolated syllables, initial segments were harder to identify than final segments. Crucially, the effects of language background and noise did not interact; the performance asymmetry between the native and non-native groups was not significantly different across signal-to-noise ratios. It is concluded that the frequently reported disproportionate difficulty of non-native listening under disadvantageous conditions is not due to a disproportionate increase in phoneme misidentifications. <s> BIB009 </s> Non-native speech perception in adverse conditions: A review <s> Non-native speech perception under energetic masking <s> This study compared monosyllabic word recognition in quiet, noise, and noise with reverberation for 15 monolingual American English speakers and 12 Spanish–English bilinguals who had learned English prior to 6 years of age and spoke English without a noticeable foreign accent. Significantly poorer word recognition scores were obtained for the bilingual listeners than for the monolingual listeners under conditions of noise and noise with reverberation, but not in quiet. Although bilinguals with little or no foreign accent in their second language are often assumed by their peers, or their clinicians in the case of hearing loss, to be identical in perceptual abilities to monolinguals, the present data suggest that they may have greater difficulty in recognizing words in noisy or reverberant listening environments. <s> BIB010 </s> Non-native speech perception in adverse conditions: A review <s> Non-native speech perception under energetic masking <s> The difficulty of listening to speech in noise is exacerbated when the speech is in the listener’s L2 rather than L1. In this study, Spanish and Dutch users of English as an L2 identified American English consonants in a constant intervocalic context. Their performance was compared with that of L1 (British English) listeners, under quiet conditions and when the speech was masked by speech from another talker or by noise. Masking affected performance more for the Spanish listeners than for the L1 listeners, but not for the Dutch listeners, whose performance was worse than the L1 case to about the same degree in all conditions. There were, however, large differences in the pattern of results across individual consonants, which were consistent with differences in how consonants are identified in the respective L1s. Index Terms: speech perception, consonants, noise, L1, L2 <s> BIB011 </s> Non-native speech perception in adverse conditions: A review <s> Non-native speech perception under energetic masking <s> Studies comparing native and non-native listener performance on speech perception tasks can distinguish the roles of general auditory and language-independent processes from those involving prior knowledge of a given language. Previous experiments have demonstrated a performance disparity between native and non-native listeners on tasks involving sentence processing in noise. However, the effects of energetic and informational masking have not been explicitly distinguished. Here, English and Spanish listener groups identified keywords in English sentences in quiet and masked by either stationary noise or a competing utterance, conditions known to produce predominantly energetic and informational masking, respectively. In the stationary noise conditions, non-native talkers suffered more from increasing levels of noise for two of the three keywords scored. In the competing talker condition, the performance differential also increased with masker level. A computer model of energetic masking in the competing talker condition ruled out the possibility that the native advantage could be explained wholly by energetic masking. Both groups drew equal benefit from differences in mean F0 between target and masker, suggesting that processes which make use of this cue do not engage language-specific knowledge. <s> BIB012 </s> Non-native speech perception in adverse conditions: A review <s> Non-native speech perception under energetic masking <s> Bilinguals are better able to perceive speech-in-noise in their native compared to their non-native language. This benefit is thought to be due to greater use of higher-level, linguistic context in the native language. Previous studies showing this have used sentences and do not allow us to determine which level of language contributes to this context benefit. Here, we used a new paradigm that isolates the semantic level of speech, in both languages of bilinguals. Results revealed that in the native language, a semantically related target word facilitates the perception of a previously presented degraded prime word relative to when a semantically unrelated target follows the prime, suggesting a specific contribution of semantics to the native language context benefit. We also found the reverse in the non-native language, where there was a disadvantage of semantic context on word recognition, suggesting that such top–down, contextual information results in semantic interference in one's second language. <s> BIB013 </s> Non-native speech perception in adverse conditions: A review <s> Non-native speech perception under energetic masking <s> This paper shows that the effect of different types of noise on recognition of different phonemes by native versus non-native listeners is highly variable, even within classes of phonemes with the same manner or place of articulation. In a phoneme identification experiment, English and Dutch listeners heard all 24 English consonants in VCV stimuli in quiet and in three types of noise: competing talker, speech-shaped noise, and modulated speech-shaped noise (all with SNRs of -6dB). Differential effects of noise type for English and Dutch listeners were found for eight consonants (/p t k g m n @? r/) but not for the other 16 consonants. For those eight consonants, effects were again highly variable: each noise type hindered non-native listeners more than native listeners for some of the target sounds, but none of the noise types did so for all of the target sounds, not even for phonemes with the same manner or place of articulation. The results imply that the noise types employed will strongly affect the outcomes of any study of native and non-native speech perception in noise. <s> BIB014 </s> Non-native speech perception in adverse conditions: A review <s> Non-native speech perception under energetic masking <s> Processing speech in a non-native language requires listeners to cope with influences from their first language and to overcome the effects of limited exposure and experience. These factors may be particularly important when listening in adverse conditions. However, native listeners also suffer in noise, and the intelligibility of speech in noise clearly depends on factors which are independent of a listener's first language. The current study explored the issue of language-independence by comparing the responses of eight listener groups differing in native language when confronted with the task of identifying English intervocalic consonants in three masker backgrounds, viz. stationary speech-shaped noise, temporally-modulated speech-shaped noise and competing English speech. The study analysed the effects of (i) noise type, (ii) speaker, (iii) vowel context, (iv) consonant, (v) phonetic feature classes, (vi) stress position, (vii) gender and (viii) stimulus onset relative to noise onset. A significant degree of similarity in the response to many of these factors was evident across all eight language groups, suggesting that acoustic and auditory considerations play a large role in determining intelligibility. Language-specific influences were observed in the rankings of individual consonants and in the masking effect of competing speech relative to speech-modulated noise. <s> BIB015
Until recently, non-native studies employed largely uninformative noise types such as stationary noise (white, pink or speech-shaped) or babble/cafeteria noise composed of six or more talkers. Lately, maskers with audible speech components, such as competing speech or a mixture of small number of talkers, have been used. The stationary/ modulated and intelligible/unintelligible distinctions lead to different masking effects, as do the types of noise. For instance, BIB006 found significantly lower scores for English word identification in white noise than in pink or aircraft noise when matched for overall level. BIB014 also highlight the highly-variable effect of different maskers which vary both in spectral and temporal patterning on sound perception in an L2. Those studies using more than one noise type have demonstrated an equivalent NL versus NNL ranking of masking effectiveness of modulated and unmodulated noises. In a consonant identification task, both NLs and NNLs in  produced highest scores for a competing speech masker, lowest for 8-talker babble and intermediate results for speech-shaped noise, with all maskers presented at 0 dB SNR. This finding was extended to three listener groups in BIB011 and listener groups from eight languages in BIB015 . Within a single type of background, signal-to-noise ratio impacts directly on the availability of low-level information for speech judgements, although redundancy of cues allows native listeners to tolerate quite significant amounts of noise. Increasing noise levels might be expected to have proportionally more impact on non-native listeners. Several studies investigated the effect of SNR differences in native versus non-native listener speech perception. Two very clear conclusions emerge from these studies. Nonnative listeners do indeed suffer more from increasing noise than natives when the task involves word or sentence processing in fixed or variable noise levels  BIB001 BIB002   BIB003 BIB004 BIB007 BIB008 BIB012 . However, for tasks which minimise or eliminate the possibility of using high-level linguistic information, noise has an equivalent overall effect on native and non-native listeners BIB005 Mackay et al., 2001a,b; BIB009 BIB010 ; even low-level predictability is better exploited by native listeners . The finding that word and sentence processing is more adversely affected for nonnative or bilingual listeners suggests that less effective use of phonotactic and contextual knowledge (particularly at the semantic level), is responsible for the non-native disadvantage. Recently, BIB013 isolated the contribution of semantics by measuring the effect of semantically-related or -unrelated items on previously-presented degraded words. Native language items facilitated the identification while non-native items produced a reduction in identification of the degraded words.