Paola Escudero

Bridging the Gap between L2 Speech Perception Research and Phonological Theory.

A series of experiments shows that Spanish learners of English acquire the ship-sheep contrast in a way specific to their target dialect (Scottish or Southern British English) and that many learners exhibit a perceptual strategy found in neither Spanish nor English. To account for these facts as well as for the findings of earlier research on second language (L2) speech perception, we provide an Optimality Theoretic model of phonological categorization that comes with a formal learning algorithm for its acquisition. Within this model, the dialect-dependent and L2-specific facts provide evidence for the hypotheses of Full Transfer and Full Access. We would like to thank the audiences of the 25th Penn Linguistics Colloquium (Philadelphia, 2001), Generative Approaches to Language Acquisition 2001 (Palmela), and EuroSLA 11 (Paderborn, 2001) and of talks in Lisbon, Amsterdam, Edinburgh, Utrecht, and Munich, all in 2001 as well, for their questions and remarks, and Rachel Hayes, Michael Sharwood Smith, and five anonymous SSLA reviewers for their helpful comments on earlier versions of this paper. This research was partially sponsored by grant 355-75-003 to Boersma from the Netherlands Organization for Scientific Research (NWO).

Novel second language words and asymmetric lexical access

The lexical and phonetic mapping of auditorily confusable L2 nonwords was examined by teaching L2 learners novel words and by later examining their word recognition using an eye-tracking paradigm. During word learning, two groups of highly proficient Dutch learners of English learned 20 English nonwords, of which 10 contained the English contrast /e/-ae/ (a confusable contrast for native Dutch speakers). One group of subjects learned the words by matching their auditory forms to pictured meanings, while a second group additionally saw the spelled forms of the words. We found that the group who received only auditory forms confused words containing /ae/ and /e/ symmetrically, i.e., both /ae/ and /e/ auditory tokens triggered looks to pictures containing both /ae/ and /e/. In contrast, the group who also had access to spelled forms showed the same asymmetric word recognition pattern found by previous studies, i.e., they only looked at pictures of words containing /e/ when presented with /e/ target tokens, but looked at pictures of words containing both /ae/ and /e/ when presented with /ae/ target tokens. The results demonstrate that L2 learners can form lexical contrasts for auditorily confusable novel L2 words. However, and most importantly, this study suggests that explicit information over the contrastive nature of two new sounds may be needed to build separate lexical representations for similar-sounding L2 words.

A cross-dialect acoustic description of vowels: Brazilian and European Portuguese

This paper examines four acoustic correlates of vowel identity in Brazilian Portuguese (BP) and European Portuguese (EP): first formant (F1), second formant (F2), duration, and fundamental frequency (F0). Both varieties of Portuguese display some cross-linguistically common phenomena: vowel-intrinsic duration, vowel-intrinsic pitch, gender-dependent size of the vowel space, gender-dependent duration, and a skewed symmetry in F1 between front and back vowels. Also, the average difference between the vocal tract sizes associated with /i/ and /u/, as measured from formant analyses, is comparable to the average difference between male and female vocal tract sizes. A language-specific phenomenon is that in both varieties of Portuguese the vowel-intrinsic duration effect is larger than in many other languages. Differences between BP and EP are found in duration (BP has longer stressed vowels than EP), in F1 (the lower-mid front vowel approaches its higher-mid counterpart more closely in EP than in BP), and in the size of the intrinsic pitch effect (larger for BP than for EP).

Native, non-native and L2 perceptual cue weighting for Dutch vowels: the case of Dutch, German, and Spanish listeners

Abstract Previous research has demonstrated that learners of English with different L1 backgrounds diverge from native speakers in their use of acoustic cues for the perception and production of vowel contrasts. This study investigated the use of two cues, i.e. , vowel spectrum and duration, for the categorization of the Dutch /aː/-/ɑ/ contrast in three groups of listeners: L1-Dutch, L1-Spanish L2-Dutch, and L1-German listeners. Three aspects of vowel contrast perception were tested: the categorical nature of the listeners’ perceptual boundary, their cue weighting, and their use of the individual cues. Experience with the Dutch language played a role in the ability to perceptually distinguish the two vowel categories: Native Dutch listeners and Spanish learners of Dutch could categorize prototypical tokens of Dutch /aː/ and /ɑ/ more reliably than L1-German listeners without experience with the Dutch language. Native Dutch listeners had the most sharply defined boundary between the two categories. The results also show that language background strongly affects vowel perception: both L1-Dutch and L1-German listeners weight vowel spectrum heavier than vowel duration, whereas L1-Spanish L2-Dutch listeners favour vowel duration. L1-German listeners’ cue weighting can be explained in terms of the cross-linguistic comparison between German and Dutch vowels. L1-Spanish L2-Dutch listeners’ results have implications for theories of second language perception.

The Effect of L1 Orthography on Non-native Vowel Perception

Previous research has shown that orthography influences the learning and processing of spoken non-native words. In this paper, we examine the effect of L1 orthography on non-native sound perception. In Experiment 1, 204 Spanish learners of Dutch and a control group of 20 native speakers of Dutch were asked to classify Dutch vowel tokens by choosing from auditorily presented options, in one task, and from the orthographic representations of Dutch vowels, in a second task. The results show that vowel categorization varied across tasks: the most difficult vowels in the purely auditory task were the easiest in the orthographic task and, conversely, vowels with a relatively high success rate in the purely auditory task were poorly classified in the orthographic task. The results of Experiment 2 with 22 monolingual Peruvian Spanish listeners replicated the main results of Experiment 1 and confirmed the existence of orthographic effects. Together, the two experiments show that when listening to auditory stimuli only, native speakers of Spanish have great difficulty classifying certain Dutch vowels, regardless of the amount of experience they may have with the Dutch language. Importantly, the pairing of auditory stimuli with orthographic labels can help or hinder Spanish listeners’ sound categorization, depending on the specific sound contrast.

Context-specific acoustic differences between Peruvian and Iberian Spanish vowels

This paper examines four acoustic properties (duration F0, F1, and F2) of the monophthongal vowels of Iberian Spanish (IS) from Madrid and Peruvian Spanish (PS) from Lima in various consonantal contexts (/s/, /f/, /t/, /p/, and /k/) and in various phrasal contexts (in isolated words and sentence-internally). Acoustic measurements on 39 speakers, balanced by dialect and gender, can be generalized to the following differences between the two dialects. The vowel /a/ has a lower first formant in PS than in IS by 6.3%. The vowels /e/ and /o/ have more peripheral second-formant (F2) values in PS than in IS by about 4%. The consonant /s/ causes more centralization of the F2 of neighboring vowels in IS than in PS. No dialectal differences are found for the effect of phrasal context. Next to the between-dialect differences in the vowels, the present study finds that /s/ has a higher spectral center of gravity in PS than in IS by about 10%, that PS speakers speak slower than IS speakers by about 9%, and that Spanish-speaking women speak slower than Spanish-speaking men by about 5% (irrespective of dialect).

Zebra finches and Dutch adults exhibit the same cue weighting bias in vowel perception

Vocal tract resonances, called formants, are the most important parameters in human speech production and perception. They encode linguistic meaning and have been shown to be perceived by a wide range of species. Songbirds are also sensitive to different formant patterns in human speech. They can categorize words differing only in their vowels based on the formant patterns independent of speaker identity in a way comparable to humans. These results indicate that speech perception mechanisms are more similar between songbirds and humans than realized before. One of the major questions regarding formant perception concerns the weighting of different formants in the speech signal (“acoustic cue weighting”) and whether this process is unique to humans. Using an operant Go/NoGo design, we trained zebra finches to discriminate syllables, whose vowels differed in their first three formants. When subsequently tested with novel vowels, similar in either their first formant or their second and third formants to the familiar vowels, similarity in the higher formants was weighted much more strongly than similarity in the lower formant. Thus, zebra finches indeed exhibit a cue weighting bias. Interestingly, we also found that Dutch speakers when tested with the same paradigm exhibit the same cue weighting bias. This, together with earlier findings, supports the hypothesis that human speech evolution might have exploited general properties of the vertebrate auditory system.

Explaining individual variation in L2 perception : rounded vowels in English learners of German

Published by Cambridge University Press in Bilingualism: Language and Cognition: http://dx.doi.org/10.1017/S1366728909990022

Second-language phonology : the role of perception

It is well known that adult learners have great difficulty when attempting to learn the sounds of a second language (L2), as observed in the phenomenon commonly known as “foreign-accented speech.” Despite the fact that adults have well-developed cognitive capabilities and have superior abilities for many complex learning and problem solving tasks, if the task is to learn the sound system of a language, adults are generally outperformed by children. How can we explain this paradox? This chapter builds a case to show that the explanation crucially involves perception.

Native Dialect Influences Second-language Vowel Perception: Peruvian Versus Iberian Spanish Learners of Dutch

Peruvian Spanish (PS) and Iberian Spanish (IS) learners were tested on their ability to categorically discriminate and identify Dutch vowels. It was predicted that the acoustic differences between the vowel productions of the two dialects, which compare differently to Dutch vowels, would manifest in differential L2 perception for listeners of these two dialects. The results show that although PS learners had higher general L2 proficiency, IS learners were more accurate at discriminating all five contrasts and at identifying six of the L2 Dutch vowels. These findings confirm that acoustic differences in native vowel production lead to differential L2 vowel perception.