A Vowel Analysis of the Northwestern University-Children\u27s Perception of Speech Evaluation Tool

In an analysis of the speech perception evaluation tool, the Northwestern University – Children’s Perception of Speech test, the goal was to determine whether the foil words and the target word were phonemically balanced across each page of test Book A, as it corresponds to the target words presented in Test Form 1 and Test Form 2 independently. Based on vowel sounds alone, variation exists in the vowels that appear on a test page on the majority of pages. The corresponding formant frequencies, at all three resonance levels for both the average adult male speaker and the average adult female speaker, revealed that the target word could be easily distinguished from the foil words on the premise of percent differences calculated between the formants of the target vowel and the foil vowels. For the population of children with hearing impairments, especially those with limited or no access to the high frequencies, the NU-CHIPS evaluation tool may not be the best indicator of the child’s speech perception ability due to significant vowel variations

Adaptation by normal listeners to upward spectral shifts of speech: Implications for cochlear implants

Multi-channel cochlear implants typically present spectral information to the wrong ''place'' in the auditory nerve array, because electrodes can only be inserted partway into the cochlea. Although such spectral shifts are known to cause large immediate decrements in performance in simulations, the extent to which listeners can adapt to such shifts has yet to be investigated. Here, the effects of a four-channel implant in normal listeners have been simulated, and performance tested with unshifted spectral information and with the equivalent of a 6.5-mm basalward shift on the basilar membrane (1.3-2.9 octaves, depending on frequency). As expected, the unshifted simulation led to relatively high levels of mean performance (e;g., 64% of words in sentences correctly identified) whereas the shifted simulation led to very poor results (e.g., 1% of words). However, after just nine 20-min sessions of connected discourse tracking with the shifted simulation, performance improved significantly for the identification of intervocalic consonants, medial vowels in monosyllables, and words in sentences (30% of words). Also, listeners were able to track connected discourse of shifted signals without lipreading at rates up to 40 words per minute. Although we do not know if complete adaptation to the shifted signals is possible, it is clear that short-term experiments seriously exaggerate the long-term consequences of such spectral shifts. (C) 1999 Acoustical Society of America. [S0001-4966(99)02012-3]

Transfer, similarity or lack of awareness? inconsistencies of German learners in the pronunciation of lot, thought, strut, palm and bath

The current study presents acoustic analyses of non-high back vowels and low central vowels in the lexical sets LOT, THOUGHT, STRUT, PALM and BATH as pronounced by German learners of English. The main objective is to show that learners of English at university level are highly inconsistent in approximating the vowels of their self-chosen target accents British English (BrE) and American English (AmE). To that end, the acoustic qualities of the English vowels of learners are compared to their native German vowels and to the vowels of native speakers of BrE and AmE. In order to facilitate statements about the effect of increased experience, the study differentiates between students in their first year at university and in their third year or later. The results obtained are highly variable: In some cases the learners transfer their L1 vowels to English, other cases show clear approximations to the target vowels, while other cases again document the production of new vowels neither found in German nor in English. However, close approximation to the target vowels only sometimes correlates with higher proficiency. This might be an indicator of a low level of awareness of systematic differences between the BrE and AmE vowel systems. But the data also indicate that the more advanced learners produce more distinct AmE BATH vowels and BrE THOUGHT vowels than the less advanced learners, which points to a partial increase of awareness resulting from increased experience. All in all it seems that raising the awareness of differences between target accents in L2 instruction is necessary if the envisage goal is for learners to reach near-native pronunciation

Loanword adaptation as first-language phonological perception

We show that loanword adaptation can be understood entirely in terms of phonological and phonetic comprehension and production mechanisms in the first language. We provide explicit accounts of several loanword adaptation phenomena (in Korean) in terms of an Optimality-Theoretic grammar model with the same three levels of representation that are needed to describe L1 phonology: the underlying form, the phonological surface form, and the auditory-phonetic form. The model is bidirectional, i.e., the same constraints and rankings are used by the listener and by the speaker. These constraints and rankings are the same for L1 processing and loanword adaptation

Cross-Linguistic Influence in the Bilingual Mental Lexicon: Evidence of Cognate Effects in the Phonetic Production and Processing of a Vowel Contrast.

The present study examines cognate effects in the phonetic production and processing of the Catalan back mid-vowel contrast (/o/-/ɔ/) by 24 early and highly proficient Spanish-Catalan bilinguals in Majorca (Spain). Participants completed a picture-naming task and a forced-choice lexical decision task in which they were presented with either words (e.g., /bɔsk/ "forest") or non-words based on real words, but with the alternate mid-vowel pair in stressed position ((*)/bosk/). The same cognate and non-cognate lexical items were included in the production and lexical decision experiments. The results indicate that even though these early bilinguals maintained the back mid-vowel contrast in their productions, they had great difficulties identifying non-words and real words based on the identity of the Catalan mid-vowel. The analyses revealed language dominance and cognate effects: Spanish-dominants exhibited higher error rates than Catalan-dominants, and production and lexical decision accuracy were also affected by cognate status. The present study contributes to the discussion of the organization of early bilinguals' dominant and non-dominant sound systems, and proposes that exemplar theoretic approaches can be extended to include bilingual lexical connections that account for the interactions between the phonetic and lexical levels of early bilingual individuals

Speaker-normalized sound representations in the human auditory cortex

The acoustic dimensions that distinguish speech sounds (like the vowel differences in “boot” and “boat”) also differentiate speakers’ voices. Therefore, listeners must normalize across speakers without losing linguistic information. Past behavioral work suggests an important role for auditory contrast enhancement in normalization: preceding context affects listeners’ perception of subsequent speech sounds. Here, using intracranial electrocorticography in humans, we investigate whether and how such context effects arise in auditory cortex. Participants identified speech sounds that were preceded by phrases from two different speakers whose voices differed along the same acoustic dimension as target words (the lowest resonance of the vocal tract). In every participant, target vowels evoke a speaker-dependent neural response that is consistent with the listener’s perception, and which follows from a contrast enhancement model. Auditory cortex processing thus displays a critical feature of normalization, allowing listeners to extract meaningful content from the voices of diverse speakers

Production of L3 Vowels: Is it Possible to Separate them from L1 and L2 Sounds?

It is incontrovertible that acquisition of a sound system of a second language is always a complex phenomenon and presents a great challenge for L2 learners (e.g. Rojczyk, 2010a). There are numerous studies (e.g. Nowacka, 2010; Flege, 1991) which show that L2 learners whose first language has a scarce number of sounds, have problems to distinguish L2 sound categories and tend to apply their L1 segments to new contexts. It may be easily detectable in the case of vowels. There is abundance of studies examining L2 learners’ successes and failures in production of L1 and L2 vowels (e.g. Flege, 1992; Nowacka, 2010; Rojczyk, 2010a). Usually such projects show how difficult it is for L2 learners to separate “old” and “new” vowel categories. However, the situation becomes much more complicated when we think of third language (L3) production. While in the case of L2 segmental production the number of factors affecting L2 sounds is rather limited (either interference from learners’ L1 or some kind of L2 intralingual influence), in the case of L3 segmental production we may encounter L1→L3, L2→L3 or L3 intralingual interference. This makes separation of L3 sounds a much more complex process. The aim of this study is to examine whether speakers of L1 Polish, L2 English and L3 German are able to separate new, L3 vowel categories from their native and L2 categories. Being a part of a larger project, this time the focus is on German /œ/. This vowel was chosen since it is regarded as especially difficult for Polish learners of German and it is frequently substituted with some other sounds. A group of English philology (Polish-English-German translation and interpretation programme) students was chosen to participate in this project. They were advanced speakers of English who did not encounter any difficulties in communication with native speakers of this language and upper-intermediate users of German. They had been taught both English and German pronunciation/practical phonetics during their studies at the University of Silesia. The subjects were asked to produce words containing analysed vowels, namely: P /u/, P /ɔ/, P /ɛ/, E /u/, E /ɔ / and G /œ/. All examined vowels were embedded in a /bVt/ context. The target /bVt/ words were then embedded in carrier sentences I said /bVt/ this time in English, Ich sag’ /bVt/ diesmal in German and Mówię /bVt/ teraz in Polish, in a non-final position. The sentences were presented to subjects on a computer screen and the produced chunks were stored in a notebook’s memory as .wav files ready for inspection. The Praat 5.3.12 speech-analysis software package (Boersma, 2001) was used to scroll through the audio files in order to locate an onset and offset of target vowels, measure the F1 and F2 frequencies and plot vowels on the plane. All analyses were also performed using Praat. The obtained results shed new light on L3 segmental production and L1 and L2 interference

Brittany Bernal - Sensorimotor Adaptation of Speech Through a Virtually Shortened Vocal Tract

The broad objective of this line of research is to understand how auditory feedback manipulations may be used to elicit involuntary changes in speech articulation. We examine speech sensorimotor adaptation to supplement the development of speech rehabilitation applications that benefit from this learning phenomenon. By manipulating the acoustics of one’s auditory feedback, it is possible to elicit involuntary changes in speech articulation. We seek to understand how virtually manipulating participants’ perception of vowel space affects their speech movements by assessing acoustic variables such as formant frequency changes. Participants speak through a digital audio processing device that virtually alters the perceived size of their vocal tract. It is hypothesized that this modification to auditory feedback will facilitate adaptive changes in motor behavior as indicated by acoustic changes resulting from speech articulation. This study will determine how modifying the perception of vocal tract size affects articulatory behavior, indicated by changes in formant frequencies and changes in vowel space area. This work will also determine if and how the size of the virtual vowel space affects the magnitude and direction of sensorimotor adaptation for speech. The ultimate aim is to determine how important it is for the virtual vowel space to mimic the talker’s real vowel space, and whether or not perturbing the size of the perceived vowel space may facilitate or impede involuntary adaptive learning for speech. Sensorimotor Adaptation of Speech Through a Virtually Shortened Vocal Tract by Brittany Bernal is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.https://epublications.marquette.edu/mcnair_2014/1009/thumbnail.jp

Native Speaker Perceptions of Accented Speech: The English Pronunciation of Macedonian EFL Learners

The paper reports on the results of a study that aimed to describe the vocalic and consonantal features of the English pronunciation of Macedonian EFL learners as perceived by native speakers of English and to find out whether native speakers who speak different standard variants of English perceive the same segments as non-native. A specially designed computer web application was employed to gather two types of data: a) quantitative (frequency of segment variables and global foreign accent ratings on a 5-point scale), and b) qualitative (open-ended questions). The result analysis points out to three most frequent markers of foreign accent in the English speech of Macedonian EFL learners: final obstruent devoicing, vowel shortening and substitution of English dental fricatives with Macedonian dental plosives. It also reflects additional phonetic aspects poorly explained in the available reference literature such as allophonic distributional differences between the two languages and intonational mismatch