Language and Speech

In the introduction to this special issue on articulatory approaches to the study of L2 speech, we first highlight the interest and unique contributions of such methods to the investigation of speech production among second language speakers. This is followed by a brief overview of the four articulatory methods—electropalatography, nasometry, magnetic resonance imaging, and ultrasound—featured in the experimental studies presented in the seven articles that constitute the issue. We then turn to an overview of the speech phenomena investigated—consonants (laterals, rhotics), vowels (individual as well as entire inventories), and sequences (both phonemic vowel-nasal sequences as well as coarticulation in phonetic sequences)—as produced by L1 speakers of various target languages (L1s: English[-Croatian], Czech, French, Japanese, Mandarin, Spanish; Target languages: English, French, Swedish). This introduction concludes with a summary of recurring acquisition themes (L1-based crosslinguistic influence, relative difficulty and target-likeness, inter-learner variability including as conditioned by individual differences) and the general speech phenomena studied (articulatory settings, gestural timing/coarticulation, effects of phonetic context).

The goal of this article is to illustrate the use of MRI for exploring bi- and multi-lingual articulatory strategies. One male and one female speaker recorded sets of static midsagittal MRIs of the whole vocal tract, producing vowels as well as consonants in various vowel contexts in either the male’s two or the female’s three languages. Both speakers were native speakers of English (American and Australian English, respectively), and both were fluent L2 speakers of French. In addition, the female speaker was a heritage speaker of Croatian. Articulatory contours extracted from the MRIs were subsequently used at three progressively more compact and abstract levels of analysis. (1) Direct comparison of overlaid contours was used to assess whether phones analogous across L1 and L2 are similar or dissimilar, both overall and in specific vocal tract regions. (2) Consonant contour variability along the vocal tract due to vowel context was determined using dispersion ellipses and used to explore the variable resistance to coarticulation for non-analogous rhotics and analogous laterals in Australian, French, and Croatian. (3) Articulatory modeling was used to focus on specific articulatory gestures (tongue position and shape, lip protrusion, laryngeal height, etc.) and then to explore the articulatory strategies in the speakers’ interlanguages for production of the French front rounded vowel series. This revealed that the Australian and American speakers used different strategies to produce the non-analogous French vowel series. We conclude that MRI-based articulatory data constitute a very rich and underused source of information that amply deserves applications to the study of L2 articulation and bilingual and multi-lingual speech.

Segment-to-segment timing overlap between Vowel-Nasal gestures in /VN/ sequences varies cross-linguistically. However, how bilinguals may adjust those timing gestures is still unanswered. Regarding timing strategies in a second language (L2), research finds that native (L1) strategies can be partially transferred to the L2, and that higher L2 proficiency promotes a more successful phonetic performance. My goal is to answer whether bilingual speakers can adjust their L1 coarticulatory settings in their L2 and to observe whether their L2 accentedness plays a role in ultimate attainment. Ten native speakers of Spanish (L1Sp) who were highly proficient L2 English speakers participated in Spanish and English read-aloud tasks. A control group of 16 L1 English speakers undertook the English experiment. Aerodynamic data were collected using pressure transducers. Each participant produced tokens with nasalized vowels in CVN# words and oral vowels in CV(CV) words. Four linguistically trained judges (two per target language) evaluated a set of pseudo-randomized sentences produced by the participants containing words with nasalized vowels and rated the speech on a 1 (heavily accented) to 9 (native-like) Likert-type scale. Measurements for onset and degree of overall nasality were obtained. Results indicate the L1Sp group can accommodate gestural timing strategies cross-linguistically as they exhibit an earlier nasality onset and increment nasality proportion in L2 English in a native-like manner. In addition, a positive correlation between greater vowel nasality degree and native-like accentedness in the L2 was found, suggesting L2 timing settings might be specified in higher spoken proficiency levels.

Rhotic sounds are some of the most challenging sounds for L2 learners to acquire. This study investigates the production of English rhotic sounds by Mandarin–English bilinguals with two English proficiency levels. The production of the English /ɹ/ by 17 Mandarin–English bilinguals was examined with ultrasound imaging and compared with the production of native English speakers. The ultrasound data show that bilinguals can produce native-like bunched and retroflex gestures, but the distributional pattern of tongue shapes in various contexts differs from that of native speakers. Acoustically, the English /ɹ/ produced by bilinguals had a higher F3 and F3–F2, as well as some frication noise in prevocalic /ɹ/, features similar to the Mandarin /ɹ/. Mandarin–English bilinguals did produce language-specific phonetic realizations for the English and Mandarin /ɹ/s. There was a positive correlation between language proficiency and English-specific characteristics of /ɹ/ by Mandarin–English bilinguals in both articulation and acoustics. Phonetic similarities facilitated rather than hindered L2 speech learning in production: Mandarin–English bilinguals showed better performance in producing the English /ɹ/ allophones that were more similar to the Mandarin /ɹ/ (syllabic and postvocalic /ɹ/s) than producing the English /ɹ/ allophone that was less similar to the Mandarin /ɹ/ (prevocalic /ɹ/). This study contributes to our understanding of the mechanism of speech production in late bilinguals.

In many English varieties, /l/ is produced differently in onsets and codas. Compared with “light” syllable-initial realizations, “dark” syllable-final variants involve reduced tongue tip-alveolar ridge contact and a raised/retracted tongue dorsum. We investigate whether native French and Spanish speakers whose L1 lacks such positionally conditioned variation can acquire English-/l/ allophony, testing the hypotheses that (1) the allophonic pattern will be acquired by both groups but (2) learners will differ from native speakers in their phonetic implementation, particularly in codas; and (3) French-speaking learners will outperform their Spanish-speaking counterparts. The production of syllable-initial and -final /l/ (singletons and clusters) in words read in isolation and a carrier sentence by 4 French- and 3 Spanish-speaking learners as well as three native English speakers was analyzed via electropalatography and acoustic analysis. While some learners produced distinct onset and coda variants and all learners had moved away to some extent from their L1 production, they differed from the native speakers in certain ways. Moreover, between- and within-group variability was observed including greater target-like anterior and posterior contact reduction in codas in the L1 French versus L1 Spanish group and generally higher F2 values in both learner groups compared with their native speaker peers. A comparison of the learners’ L1 and L2 production revealed L1-based patterns of positional reduction of the tongue tip and dorsum gestures. We conclude by addressing the contributions of EPG to our understanding of L2 speech and highlight avenues for future research including the study of both linguistic and speaker variables.

This paper presents L2 vowel remediation in a classroom setting via two real-time visual feedback methods: articulatory ultrasound tongue imaging, which shows tongue shape and position, and a newly developed acoustic formant analyzer, which visualizes a point correlating with the combined effect of tongue position and lip rounding in a vowel quadrilateral. Ten Czech students of the Swedish language participated in the study. Swedish vowel production is difficult for Czech speakers since the languages differ significantly in their vowel systems. The students selected the vowel targets on their own and practiced in two classroom groups, with six students receiving two ultrasound training lessons, followed by one acoustic, and four students receiving two acoustic lessons, followed by one ultrasound. Audio data were collected pre-training, after the two sessions employing the first visual feedback method, and at post-training, allowing measuring Euclidean distance among selected groups of vowels and observing the direction of change within the vowel quadrilateral as a result of practice. Perception tests were performed before and after training, revealing that most learners perceived selected vowels correctly already before the practice. The study showed that both feedback methods can be successfully applied to L2 classroom learning, and both lead to the improvement in the pronunciation of the selected vowels, as well as the Swedish vowel set as a whole. However, ultrasound tongue imaging seems to have an advantage as it resulted in a greater number of improved targets.

This study examines how L1 English-L2 French learners use L1 articulatory and acoustic categories to produce L2 vowels that are both similar to and different from their L1 vowels. Previous studies examining the relationship between L1 and L2 sound inventories have found that learners reuse L1 phone categories to produce L2 phones that are perceived as similar, but importantly, there is a lack of articulatory data included in these types of studies, which has reinforced the assumption that vowel categories can be solely represented by their acoustic properties. The present study uses ultrasound tongue imaging data and videos of lip rounding in addition to acoustic data to examine how L1 English-L2 French learners produce the French vowels /i y u e ø o/ compared with their English vowels /i u e o/. The results focus on individual paths to category formation to show how learners articulate L2 vowels, and reveal that they tend to reuse L1 tongue body gestures to produce the French vowels /i u e o/, and lip rounding gestures to produce the round vowels /y u o/. This study demonstrates that transfer of articulatory gestures depends on vowel quality and emphasizes the importance of using articulatory data to inform theories of L2 category formation.

Articulatory setting, the underlying tendency of the articulators to assume a certain overall configuration during speech, is language-specific and can be measured by observing the inter-speech posture (ISP) of the articulators during the brief pauses between utterances. To determine a given language’s ISP, observing bilingual speakers in each of their languages is ideal, so that questionable normalization across different vocal tracts does not have to be done. In this study, four English–Japanese bilinguals of various English proficiencies participated. To this end, we quantitatively tested for the existence of two settings in each bilingual, and the results showed no systematic differences between the tongue ISPs of Japanese and English. We also tried to shed light on the origin of articulatory setting, which is thought to emerge from the configurations of the most frequent phonemes of a language. We qualitatively compared the predicted ISP based on Japanese spoken frequency of occurrence data with the mean measured ISP in Japanese. Ultrasound movies of the tongue were recorded and analyzed, and the results showed that for three participants, the predicted ISP’s tongue tip and blade were substantially lower than for the mean measured ISP. The mean measured ISPs also displayed greater variability in English (L2) than in Japanese (L1), much more so in the lower proficiency English speakers.