Estimates of Speech Efficiency in Monolingual and Bilingual Speakers of English.

INTRODUCTION: The Speech Efficiency Score (SES) serves as an acoustic metric for assessing fluency in conversational speech within the temporal domain. This study leverages SES to investigate conversational speech efficiency among native speakers of American English (AE) compared to speakers of Mandarin-accented English (MAE). METHODS: SES, speaking rate, articulation rate, and vocabulary diversity were measured and compared between two groups: native AE speakers and MAE speakers. The study utilized conversational speech samples collected from both groups to analyze these metrics. RESULTS: Findings indicate a disparity in speaking rate and articulation rate between the AE and MAE groups, with the AE group exhibiting significantly faster speech. However, no significant differences were observed in SES and vocabulary diversity between the two groups. CONCLUSION: The results are discussed in the context of the interplay between speaking rate, speech fluency, and vocabulary diversity. These findings shed light on the maintenance of speech efficiency among bilingual speakers, suggesting that despite differences in speaking rate and articulation rate, SES and vocabulary diversity remain comparable between native AE speakers and MAE speakers.

The different effects of a sensorimotor grounding on AoA between bilingual concepts.

Introduction: Psycholinguistic studies have argued for the age of acquisition (AoA) of words as a marker of concept learning, showing that the semantic features of concepts themselves influence the age at which their labels are learned. However, empirical evidence suggests that semantic features such as imageability and linguistic phenomena such as frequency do not adequately predict AoA. The present study takes the developmental approach of embodied cognition and investigates the effects of sensorimotor experiences on the ease of acquisition of the concept acquired in bilinguals. Specifically, we investigated (1) whether the sensorimotor experience can explain AoA beyond frequency; (2) and whether these patterns are consistent across L1 Chinese and L2 English. Methods: We conducted sensorimotor rating measures in both Chinese and English on 207 items in which Chinese-English bilingual adults were requested to evaluate the extent to which they experienced concepts by employing six perceptual senses and five effectors for actions located in various regions of the body. Meanwhile, data on AoA and frequency were collected. Results: The present study showed the sensorimotor experience was closely linked with AoAs in both languages. However, the correlation analysis revealed a trend of higher correlations between AoAs for the same concepts and L1 Chinese, relative to L2 English for the present Chinese-English bilinguals. Importantly, the hierarchical regression analysis demonstrated that after controlling for frequency, sensorimotor experience explained additional variance in L1 AoA. However, L2 sensorimotor experience did not explain the variance in L2 AoA. Sensorimotor experience explained more share of variance in L1 AoA but frequency accounted for more variance in L2 AoA. Discussion: The findings suggest that concept acquisition should consider the grounding in appropriate sensorimotor experience beyond linguistic phenomena like frequency.

Effects of Orthographic Input and Inhibitory Control on Second-Language Speech Production.

The present study extends previous research reporting that orthographic forms, such as the use of a single letter or two letters to indicate the same sound, affect sound duration in second-language (L2) production. Native-language (L1) Korean L2 English sequential bilinguals performed a delayed repetition task for word pairs containing the same consonant or vowel spelled with one or two letters. Korean provided an interesting case because (1) it has an alphabetic orthographic system but not a Roman alphabet and thus, there may be no interorthographic interference and (2) it has no phonemic length contrast for vowels, whereas there is some disagreement on the contrastiveness of the consonant length, which can lead to an asymmetry in the grapheme-to-phoneme correspondence between vowels and consonants. The results showed that Korean learners produced the same English vowel with a short duration when spelled with a single letter and with a long duration when spelled with double letters or digraphs composed of two different letters; this variation in duration did not appear when producing English consonants spelled with a single or two letters. This study further examined whether individual differences in inhibitory control influenced the magnitude of orthographic effects in the production of English vowels by Korean learners. Individual differences in inhibitory control were not strongly related to the influence of orthography on vowel production.

L1 variation and L2 acquisition: L1 German /eː/-/ɛː/ overlap and its effect on the acquisition of L2 English /ɛ/-/æ/.

A person's first language (L1) affects the way they acquire speech in a second language (L2). However, we know relatively little about the role different varieties of the L1 play in the acquisition of L2 speech. This study focuses on German (L1) learners of English (L2) and asks whether the degree to which German speakers distinguish between the two vowels /eː/ and /ɛː/ in their L1 has an impact on how well these individuals identify /æ/ and discriminate between the two English vowels /ɛ/ and /æ/. These two English vowels differ in both vowel quality and duration (/æ/ is longer than /ɛ/). We report on an identification and a discrimination experiment. In the first study, participants heard a sound file and were asked to indicate whether they heard "pen" or "pan" (or "pedal" or "paddle"). The stimuli differed from each other in terms of both vowel quality (11 steps on a spectral continuum from an extreme /æ/ to an extreme /ɛ/) and duration (short, middle, long). In the second study, participants had to signal whether two sound files they were exposed to differed from each other. We modeled the percentage of /æ/ ("pan," "paddle") selection (identification task only, binomial logistic regression), accuracy (discrimination task only, binomial logistic regression), and reaction time (identification and discrimination tasks, linear mixed effects models) by implementing the German Pillai score as a measure of vowel overlap in our analysis. Each participant has an individual Pillai score, which ranges from 0 (= merger of L1 German /eː/ and /ɛː/) to 1 (=maintenance of the contrast between L1 German /eː/ and /ɛː/) and had been established, prior to the perception experiments reported here, in a production study. Although the findings from the discrimination study remain inconclusive, the results from the identification test support the hypothesis that maintaining the vowel contrast in the L1 German leads to a more native-like identification of /æ/ in L2 English. We conclude that sociolinguistic variation in someone's L1 can affect L2 acquisition.

Data on English coda voicing contrast under different prosodic conditions produced by American English speakers and Korean learners of English.

This data article provides acoustic data for individual speakers' production of coda voicing contrast between stops in English, which are based on laboratory speech recorded by twelve native speakers of American English and twenty-four Korean learners of English. There were four pairs of English monosyllabic target words with voicing contrast in the coda position (bet-bed, pet-ped, bat-bad, pat-pad). The words were produced in carrier sentences in which they were placed in two different prosodic boundary conditions (Intonational Phrase initial and Intonation Phrase medial), two pitch accent conditions (nuclear-pitch accented and unaccented), and three focus conditions (lexical focus, phonological focus and no focus). The raw acoustic measurement values that are included in a CSV-formated file are F0, F1, F2 and duration of each vowel preceding a coda consonant; and Voice Onset Time of word-initial stops. This article also provides figures that exemplify individual speaker variation of vowel duration, F0, F1 and F2 as a function of focus conditions. The data can thus be potentially reused to observe individual variations in phonetic encoding of coda voicing contrast as a function of the aforementioned prosodically-conditioned factors (i.e., prosodic boundary, pitch accent, focus) in native vs. non-native English. Some theoretical aspects of the data are discussed in the full-length article entitled "Phonetic encoding of coda voicing contrast under different focus conditions in L1 vs. L2 English" [1].

Prosodic Structural Effects on Non-Contrastive Coarticulatory Vowel Nasalization in L2 English by Korean Learners.

This acoustic study explores how Korean learners produce coarticulatory vowel nasalization in English that varies with prosodic structural factors of focus-induced prominence and boundary. N-duration and A1-P0 (degree of V-nasalization) are measured in consonant-vowel-nasal (CVN) and nasal-vowel-consonant (NVC) words in various prosodic structural conditions (phrase-final vs. phrase-medial; focused vs. unfocused). Korean learners show a systematic fine-tuning of the non-contrastive V-nasalization in second language (L2) English in relation to prosodic structure, although it does not pertain to learning new L2 sound categories (i.e., L2 English nasal consonants are directly mapped onto Korean nasal consonants). The prosodic structurally conditioned phonetic detail in English appears to be accessible in most part to Korean learners and was therefore reflected in their production of L2 English. Their L2 production, however, is also found to be constrained by their first language (L1-Korean) to some extent, resulting in some phonetic effects that deviate from both L1 and L2. The results suggest that the seemingly low-level coarticulatory process is indeed under the speaker's control in L2, which reflects interactions of the specificities of the phonetics-prosody interface in L1 and L2. The results are also discussed in terms of their implications for theories of L2 phonetics.

Morphological Priming Effects in L2 English Verbs for Japanese-English Bilinguals.

For native (L1) English readers, masked presentations of past-tense verb primes (e.g., fell and looked) produce faster lexical decision latencies to their present-tense targets (e.g., FALL and LOOK) than orthographically related (e.g., fill and loose) or unrelated (e.g., master and bank) primes. This facilitation observed with morphologically related prime-target pairs (morphological priming) is generally taken as evidence for strong connections based on morphological relationships in the L1 lexicon. It is unclear, however, if similar, morphologically based, connections develop in non-native (L2) lexicons. Several earlier studies with L2 English readers have reported mixed results. The present experiments examine whether past-tense verb primes (both regular and irregular verbs) significantly facilitate target lexical decisions for Japanese-English bilinguals beyond any facilitation provided by prime-target orthographic similarity. Overall, past-tense verb primes facilitated lexical decisions to their present-tense targets relative to both orthographically related and unrelated primes. Replicating previous masked priming experiments with L2 readers, orthographically related primes also facilitated target recognition relative to unrelated primes, confirming that orthographic similarity facilitates L2 target recognition. The additional facilitation from past-tense verb primes beyond that provided by orthographic primes suggests that, in the L2 English lexicon, connections based on morphological relationships develop in a way that is similar to how they develop in the L1 English lexicon even though the connections and processing of lower level, lexical/orthographic information may differ. Further analyses involving L2 proficiency revealed that as L2 proficiency increased, orthographic facilitation was reduced, indicating that there is a decrease in the fuzziness in orthographic representations in the L2 lexicon with increased proficiency.

Explaining L2 Lexical Learning in Multiple Scenarios: Cross-Situational Word Learning in L1 Mandarin L2 English Speakers.

Adults commonly struggle with perceiving and recognizing the sounds and words of a second language (L2), especially when the L2 sounds do not have a counterpart in the learner's first language (L1). We examined how L1 Mandarin L2 English speakers learned pseudo English words within a cross-situational word learning (CSWL) task previously presented to monolingual English and bilingual Mandarin-English speakers. CSWL is ambiguous because participants are not provided with direct mappings of words and object referents. Rather, learners discern word-object correspondences through tracking multiple co-occurrences across learning trials. The monolinguals and bilinguals tested in previous studies showed lower performance for pseudo words that formed vowel minimal pairs (e.g., /dit/-/dɪt/) than pseudo word which formed consonant minimal pairs (e.g., /bɔn/-/pɔn/) or non-minimal pairs which differed in all segments (e.g., /bɔn/-/dit/). In contrast, L1 Mandarin L2 English listeners struggled to learn all word pairs. We explain this seemingly contradicting finding by considering the multiplicity of acoustic cues in the stimuli presented to all participant groups. Stimuli were produced in infant-directed-speech (IDS) in order to compare performance by children and adults and because previous research had shown that IDS enhances L1 and L2 acquisition. We propose that the suprasegmental pitch variation in the vowels typical of IDS stimuli might be perceived as lexical tone distinctions for tonal language speakers who cannot fully inhibit their L1 activation, resulting in high lexical competition and diminished learning during an ambiguous word learning task. Our results are in line with the Second Language Linguistic Perception (L2LP) model which proposes that fine-grained acoustic information from multiple sources and the ability to switch between language modes affects non-native phonetic and lexical development.

Establishing New Mappings between Familiar Phones: Neural and Behavioral Evidence for Early Automatic Processing of Nonnative Contrasts.

To attain native-like competence, second language (L2) learners must establish mappings between familiar speech sounds and new phoneme categories. For example, Spanish learners of English must learn that [d] and [ð], which are allophones of the same phoneme in Spanish, can distinguish meaning in English (i.e., /deɪ/ "day" and /ðeɪ/ "they"). Because adult listeners are less sensitive to allophonic than phonemic contrasts in their native language (L1), novel target language contrasts between L1 allophones may pose special difficulty for L2 learners. We investigate whether advanced Spanish late-learners of English overcome native language mappings to establish new phonological relations between familiar phones. We report behavioral and magnetoencepholographic (MEG) evidence from two experiments that measured the sensitivity and pre-attentive processing of three listener groups (L1 English, L1 Spanish, and advanced Spanish late-learners of English) to differences between three nonword stimulus pairs ([idi]-[iði], [idi]-[iɾi], and [iði]-[iɾi]) which differ in phones that play a different functional role in Spanish and English. Spanish and English listeners demonstrated greater sensitivity (larger d' scores) for nonword pairs distinguished by phonemic than by allophonic contrasts, mirroring previous findings. Spanish late-learners demonstrated sensitivity (large d' scores and MMN responses) to all three contrasts, suggesting that these L2 learners may have established a novel [d]-[ð] contrast despite the phonological relatedness of these sounds in the L1. Our results suggest that phonological relatedness influences perceived similarity, as evidenced by the results of the native speaker groups, but may not cause persistent difficulty for advanced L2 learners. Instead, L2 learners are able to use cues that are present in their input to establish new mappings between familiar phones.