F2 Onset Research Articles

Tone-vowel interaction and co-articulation in Cantonese speakers with apraxia of speech and co-existing aphasia: a preliminary study

ABSTRACT Background Speakers with apraxia of speech (AOS) usually produce segmental and prosodic errors that influence their speech intelligibility. Literature on AOS in tonal language speakers is sparse compared to that in non-tonal language. Also, the existing research often made static, isolated analyses, leaving the production and co-articulation between segments and suprasegmental entities in tonal languages under-investigated. Aims This preliminary study aims to fulfill the aforementioned research gaps by investigating vowel-tone interaction and tonal and vocalic co-articulation in Cantonese post-stroke speakers with AOS. Methods Five Cantonese adults with AOS post-stroke, five adults without AOS post-stroke, and five healthy controls performed the Tone Sequencing Task (TST), a task adapted from oral diadochokinetic tasks that required five rapid repetitions of 3-syllable items formed by three different Cantonese vowels and three different Cantonese tones. The quality of vowels was indexed by midpoint formant values and euclidean distances between the vowels. Within-speaker variation was assessed by coefficients of variance. Co-articulation was indexed by onset and offset formant or f0 values. The effects of the participant groups, the positions of tone-syllable in the TST stimuli, and the tones carried by vowels/carrying vowels were evaluated with linear mixed effect models. Results Cantonese-speaking adults with AOS had difficulty in producing distinctive vowels and tones. They also showed large within-speaker variation in vowel production but reduced tone contrast, especially at the final positions. The disrupted anticipatory co-articulation between vowels as well as between tones further suggested that the speakers with AOS could not sequence segments and suprasegments simultaneously.

Infant preference for specific phonetic cue relations in the contrast between voiced and voiceless stops.

Acoustic variability in the speech input has been shown, in certain contexts, to be beneficial during infants' acquisition of sound contrasts. One approach attributes this result to the potential of variability to make the stability of individual cues visible. Another approach suggests that, instead of highlighting individual cues, variability uncovers stable relations between cues that signal a sound contrast. Here, we investigate the relation between Voice Onset Time and the onset of F1 formant frequency, two cues that subserve the voicing contrast in German. First, we verified that German-speaking adults' use of VOT to categorize voiced and voiceless stops is dependent on the value of the F1 onset frequency, in the specific form of a so-called trading relation. Next, we tested whether 6-month-old German learning infants exhibit differential sensitivity to stimulus continua in which the cues varied to an equal extent, but either adhered to the trading relation established in the adult experiment or adhered to a reversed relation. Our results present evidence that infants prefer listening to speech in which phonetic cues conform to certain cue trading relations over cue relations that are reversed.

On the temporal aspect of post-consonantal fundamental frequency perturbation in English voicing perception

The fundamental frequency (F0) after English voiceless obstruents is generally higher than their voiced counterparts. This difference is usually largest at the vowel onset and diminishes before the vowel ends. Past research has established that the F0 perturbation influences English listeners' voicing perception. While many studies have highlighted the effect of F0 onset height, the temporal extent of the F0 perturbation is less investigated. In the present study, listeners categorized bilabial stops as voiced or voiceless. We manipulated the voice onset time (VOT), the F0 contour, and the presence of background noise. Except for one level contour at the baseline F0 value, all other F0 contours started at 20 Hz higher than the baseline. Critically, these contours fell to reach baseline at different times, rendering them different slopes. The experimental results revealed an interaction between VOT, F0, and noise. Specifically, when the stimuli were presented in noise and had VOTs near the category boundary, listeners were more likely to categorize F0 falling at slower rates as voiceless than those at faster rates. These results suggested that the duration of F0 perturbation also affects voicing perception in English and might play a role in developing tonal languages.

Perceptual compensation for vowel intrinsic f0 effects in native English speakers.

High vowels have higher f0 than low vowels, creating a context effect on the interpretation of f0. Since onset F0 is a cue to stop voicing, the vowel context is expected to influence voicing judgements. Listeners categorized syllables starting with high ("bee"-"pea") and low ("bye"-"pie") vowels varying orthogonally in VOT and onset F0. Listeners made use of both cues as expected. Furthermore, vowel height affected listeners' categorization. Syllables with the low vowel /a/ elicited more voiceless responses compared to syllables with the high vowel /i/. This suggests that listeners compensate for vowel intrinsic effects when making other phonemic judgements.

Enhancement of laryngeal contrasts in non-native English clear speech: a comparison between L2-immersed sequential bilinguals and L1-immersed speakers.

Clear speech, a speaking style used to mitigate communicative circumstances affecting the transmission or decoding of speech signal, often involves the enhancement of language-specific phonological contrasts, including laryngeal contrasts. This study investigates the role of language dominance in the implementation of language-specific laryngeal contrasts in L2 clear speech. Two groups of Korean-English speakers (L1 Korean) were tested: a relatively less Korean-dominant L2-immersed group of sequential bilinguals (N = 30) and a strongly Korean-dominant L1-immersed group (N = 30), with dominance assessed based on the results of the Bilingual Language Profile. Participants read a set of English minimal pairs differing in the voicing of word-initial stops (e.g., tab vs. dab), and their acoustic enhancement strategies were compared with those of native English speakers (N = 20). As correlates of the English laryngeal contrast, voice onset time (VOT) and onset f0 were measured. Results showed that both bilingual groups enhanced English laryngeal contrast in clear speech via voiceless VOT lengthening, similarly to native English speakers, but to a smaller extent than native speakers. Both bilingual groups also implemented a greater degree of onset f0 difference between voiced and voiced English stops than native English speakers did, although no enhancement of this parameter was observed in their clear speech. Surprisingly, no significant differences were found between L2- and L1-immersed speakers, suggesting a lack of language immersion effect on the acoustic enhancement strategies in L2 clear speech. We discuss possible explanations for this finding and propose directions for future research.

Visual cues in sound change: A cross-modal perceptual account for the typological rarity of labial palatalization

Auditory perceptibility is widely recognized as a major contributing factor to listener-based sound change. Although speech perception is also known to be influenced by vision, the role of visual cues in facilitating or inhibiting sound change is not well understood. Palatalization of /tʲ/ and /kʲ/ to /tʃ/ is a typologically common change that is frequently attributed to misperception, while full palatalization of labial consonants is exceedingly rare. We test whether visual cues contribute to this asymmetry by way of the visual distinctiveness of labial closure. An audiovisual perception experiment was conducted in which 40 native Korean speakers were presented with synthetically altered tokens along 5-step continua from /pʰ/, /tʰ/, or /kʰ/ to /t?ɕ/ in audio-only, audiovisual-congruent, and audiovisual-incongruent conditions. Acoustic cues to place of articulation, F2 onset, and spectral frequency during aspiration, were manipulated. Results show that presence of the visual lip closure cue significantly inhibited perception of labials as palatals: the /pʰ/-/tɕʰ/ boundary was shifted toward /tɕʰ/ in the AV-congruent group, and labials were more likely to be perceived as palatals in the absence of lip closure. This finding suggests that visual speech cues may contribute to the typological asymmetry and that sound change can be modulated by visual cues.

An quantitative analysis of Punjabi tones

Punjabi has three tones, the falling and the rising tones developed due to the historically lost voiced aspirated consonants and word-final glottal fricative /ɦ/, and the default tone occurred elsewhere. While there has been some experimental research on Punjabi tones, there have been limitations due few stimuli and speakers. The main aim of the current study was to provide a phonetic examination of the fundamental frequency (f0) patterns across a large number of Punjabi words produced by multiple speakers. The experiment was conducted online using 24 native speakers (9F, 15M) of Indian Punjabi. The list of stimuli contained 66 monosyllabic words (default = 18, falling = 15, rising = 33) with either /a/ or /ə/. The speakers were recorded producing the stimuli in carrier and natural sentence environments. Linear mixed effects analyses were conducted on six f0 measures: the onset, mid, and offset of the vowel, the f0 range (MaxF0-MinF0), and the f0 trajectory in the first (MidF0-BegF0) and final (EndF0-MidF0) halves of the vowel. The results confirmed three distinct pitch curves for the three tones. Each of the three tones were distinguished from one another for the onset f0 and the EndF0-MidF0 measures. Vowel quality influenced tone realization. Between-speaker and word variation was observed.

Short-term, not long-term, average spectra of preceding sentences bias consonant categorization.

Speech sound perception is influenced by the spectral properties of surrounding sounds. For example, listeners perceive /g/ (lower F3 onset) more often after sounds with prominent high-F3 frequencies and perceive /d/ (higher F3 onset) more often after sounds with prominent low-F3 frequencies. These biases are known as spectral contrast effects (SCEs). Much of this work examined differences between long-term average spectra (LTAS) of preceding sounds and target speech sounds. Post hoc analyses by Stilp and Assgari [(2021) Atten. Percept. Psychophys. 83(6) 2694-2708] revealed that spectra of the last 475 ms of precursor sentences, not the entire LTAS, best predicted biases in consonant categorization. Here, the influences of proximal (last 500 ms) versus distal (before the last 500 ms) portions of precursor sentences on subsequent consonant categorization were compared. Sentences emphasized different frequency regions in each temporal window (e.g., distal low-F3 emphasis, proximal high-F3 emphasis, and vice versa) naturally or via filtering. In both cases, shifts in consonant categorization were produced in accordance with spectral properties of the proximal window. This was replicated when the distal window did not emphasize either frequency region, but the proximal window did. Results endorse closer consideration of patterns of spectral energy over time in preceding sounds, not just their LTAS.

Crosslinguistic differences in cue primacy affect bilinguals' discrimination performance

Onset f0 – pitch at the onset of the vowel following the consonant – is an important cue to laryngeal stop distinctions in Korean, especially the lenis-aspirated contrast, while in English onset f0 plays only a secondary role in distinguishing voiced and voiceless stops. The current study investigates to what extent Korean heritage speakers (n = 29) who are English dominant can perceptually discriminate Korean lenis and aspirated stops differing acoustically only in terms of onset f0, but not in terms of VOT. Heritage speakers’ performance is compared to that of Korean-immersed native speakers as a control group (n = 29). We hypothesized that heritage speakers would experience more difficulty than Korean-immersed speakers in using onset f0 as the sole cue to laryngeal contrast, due to the influence from English, where VOT dominates onset f0 as a cue to voicing. The results of a mixed-effects logistic regression model confirmed that heritage speakers were less accurate in the lenis-aspirated discrimination task than Korean-immersed speakers, providing support to the hypothesis that bilinguals’ perception of their first language speech can be subject to crosslinguistic influence from their second language.

Crosslinguistic influence in bilingual production of clear speech

Clear speech, a listener-oriented speaking style adopted to mitigate communicative barriers, is often characterized by language-specific acoustic enhancement of phonological contrasts (Smiljanic and Bradlow, 2008; Cho et al., 2011). Previous work (e.g., Smiljanic and Bradlow, 2009) suggested a possibility that bilingual speakers’ L1 and L2 clear speech strategies could affect each other. The current study examined English and Korean clear speech produced by late Korean-English bilinguals (n = 30) living in the United States. Their clear speech produced in each of the two languages was compared with clear speech produced by either English (n = 20) or Korean (n = 20) monolinguals. Of specific interest was how English and Korean stop contrasts were realized and enhanced in clear speech with respect to the use of VOT and onset F0. The bilinguals enhanced the English voicing contrast in the same manner as English monolinguals, via asymmetrical lengthening of voiceless stops’ VOT. In Korean clear speech, bilinguals also lengthened VOT of the aspirated and lenis (long-lag) stops, whereas Korean monolinguals did not exhibit the same pattern. These findings suggest that Korean clear speech strategies produced by the bilinguals could be affected by their L2, due to their extensive exposure to the language.

Closure durations of Korean stops at three positions

This study investigates closure durations of Korean stops in terms of laryngeal contrasts, places of articulation, and three positions within words. Twenty-two Korean speakers produced the nonsense words containing Korean stops found in word-initial and word-final positions and between vowels. The statistical results showed that the closure durations differed significantly by laryngeal contrast and place of articulation. In addition, the differences by position within words were marginally significant. The closure durations were in the order of lenis < aspirated < fortis stops by laryngeal contrast, velar < alveolar < bilabial stops by place of articulation, and word-final < word-initial < between vowels by positions within words. The laryngeal contrasts were neutralized in word-final position as per coda neutralization in Korean phonology. This study shows that closure durations should be considered a valuable phonetic cue to identify stops on par with voice onset time and f0.

A potential approach for reducing hearing difficulty by improving perception of intensity changes in speech

Many listeners report hearing difficulty, especially for speech in noisy environments, despite having normal audiometric thresholds. Recent work suggests that such cases may be caused by disruptions in coding of suprathreshold sounds at early stages of auditory processing. Specifically, differences in the function of auditory nerve fibers with lower spontaneous firing rates could disrupt coding of intensity changes for sounds in the typical range used for speech communication. In turn, this could affect perception of acoustic cues in speech that are dependent on intensity changes over time, such as voice onset time (VOT). The current study investigated a speech sound manipulation designed to counteract the effects of such disruptions by making intensity differences in the signal more pronounced. Listeners heard speech sounds varying along two acoustic dimensions that provide information about word-initial voicing, VOT and f0 onset, and categorized sounds as either voiced or voiceless. Results showed that the intensity manipulation reduced listeners' use of f0 for voicing categorization and also affected their use of VOT. This suggests that intensity manipulations can make acoustic cues like VOT more salient, providing a potential treatment approach for listeners who have difficulty coding intensity differences in speech.

Acoustic cues to the perception of Danish stød

This study examines the effect of F0 and creak (raspiness) on Danish stød perception. Stød is typically characterized by high fundamental frequency (F0) at the beginning of the syllable and low F0, often with creaky phonation, at the end of the syllable (Fischer-Jørgensen, 1989). However, it is not clear how these acoustic cues, high F0 at rhyme onset, low F0 at rhyme offset, and creak, contribute to the percept of stød for listeners. A nonce word ABX task and a perceptual rhyming task were conducted. Results from the ABX task indicate that nonce words with high-mid or high-low F0 contours and added raspiness (Corretge, 2012) or a sustained high F0 with or without raspiness were more likely to be considered the “same” as naturally produced nonce words with stød. In the rhyming task, nonce words with high F0 and raspiness were significantly more likely to be considered as rhyming with a naturally produced real word with stød for all tonal contours tested. Overall, the results indicate that both high F0 onset{Citation} and creaky phonation contribute to the stød percept. Furthermore, both cues were almost always needed to increase stød responses in both tasks, suggesting little evidence of cue trading.

The dual role of post-stop fundamental frequency in the production and perception of stops in Mandarin-English bilinguals

In non-tonal languages with a two-way laryngeal contrast, post-stop fundamental frequency (F0) tends to vary as a function of phonological voicing in stops, and listeners use it as a cue for stop voicing. In tonal languages, F0 is the most important acoustic correlate for tone, and listeners likewise rely heavily on F0 to differentiate tones. Given this ambiguity of F0 in its ability to signal phonological voicing and tone, how do speakers of a tonal language weight it in production and perception? Relatedly, do bilingual speakers of tonal and non-tonal languages use the same weights across different language contexts? To address these questions, the cross-linguistic performances from L1 (first language) Mandarin-L2 (second language) English bilinguals dominant in Mandarin in online production and perception experiments are compared. In the production experiment, the participant read aloud Mandarin and English monosyllabic words, the onsets of which typified their two-way laryngeal contrast. For the perception experiment, which utilized a forced-choice identification paradigm, both the English and Mandarin versions shared the same target audio stimuli, comprising monosyllables whose F0 contours were modeled after Mandarin Tone 1 and Tone 4, and whose onset was always a bilabial stop. The voice onset time of the bilabial stop and the onset F0 of the nucleus were manipulated orthogonally. The production results suggest that post-stop F0 following aspirated/voiceless stops was higher than that following unaspirated/voiced stops in both Mandarin and English production. However, the F0 difference in English was larger as compared to Mandarin, indicating that participants assigned more production weight to post-stop F0 in English than in Mandarin. On the perception side, participants used post-stop F0 as a cue in perceiving stops in both English and Mandarin, with higher post-stop F0 leading to more aspirated/voiceless responses, but they allocated more weight to post-stop F0 when interpreting audio stimuli as English words than as Mandarin words. Overall, these results argue for a dual function of F0 in cueing phonological voicing in stops and lexical tone across production and perception in Mandarin. Furthermore, they suggest that bilinguals are able to dynamically adjust even a secondary cue according to different language contexts.

Egyptian vowel second formant in isolation and in transition following high-frequency fricatives by NLFC hearing aid in children: how does the pattern compare to typically hearing peers?

BackgroundHigh-frequency consonants form an area of difficulty among children with hearing impairment. Many technological setups have emerged in order to improve their audibility, among them nonlinear frequency compression (NLFC). Therefore, the following study was carried out in order to evaluate change in production of high-frequency fricatives by hearing-impaired children utilizing NLFC hearing aids. This was through spectrographic analysis of F2 onset of transition elicited by fricatives in a prevocalic context, and results were compared to typically developing (TD) children. A change in mid-frequency sounds due to high-frequency compression was also tested through production of sustained vowels in isolation.ResultsA preliminary prospective case-control study involved 9 patients with NLFC hearing aids, evaluated at 1- and at 6-month post-fitting, without receiving speech therapy. Spectrographic analysis of F2 formant onset in [a] and [i] vowels when combined with [s] and [f] fricatives in a CV (consonant-vowel) pattern, presented auditorily and audio-visually, was observed and analyzed. One patient was excluded due to noncompliance in attendance. In the 8 patients who completed the study, very high-frequency level of F2 onset in CV was notable in second versus first evaluation in NLFC group, to the extent of surpassing the typical value in TD control group with [i] vowel. Contrastingly, F2 of sustained vowels in isolation took a trend of a lower value after 6 months of NLFC hearing aid use, as compared to the first evaluation. Consequently, the gap between sustained vowel F2 level in TD and NLFC groups widened.ConclusionMean high-frequency range of F2 onset of transition in CV patterns of voiceless fricatives [s] and [f] with [i] and [a] vowels 6 months after NLFC fitting reflects an enhancement in the frequency range production of these sounds. A shift toward a lower F2 frequency range in sustained mid-frequency vowels, on the other hand, remains to be carefully investigated as a sequel of nonlinear frequency compression in the Egyptian hearing-impaired children.

Individual Differences in Categorical Judgment of L2 Stops: A Link to Proficiency and Acoustic Cue-Weighting.

This study investigated individual differences in Korean adult learners' categorical perception of L2 English stops with an aim to explore the relationship of gradient categorizations to perceptual sensitivity to acoustic cues and L2 proficiency. Korean young adult L2 learners of English (N = 49) participated in two speech perception tasks (visual analog scaling and forced-choice identification) in which they listened to English voiced and voiceless stops and Korean lax and aspirated stops with Voice Onset Time (VOT) and F0 manipulated to form a continuum. It was found that in both L1 and L2 stop perception, listeners' gradient category judgment was associated with greater reliance on language-specific redundant cues (i.e., F0 in L2 English and VOT in L1 Korean) and that in the perception of L2 stops, categorical listeners who tended to be less sensitive to F0 were the ones with a higher level of L2 English proficiency. The results suggest that the categorical manner of judging L2 stops reflects learners' better knowledge of L2-specific acoustic cue-weightings, based on which less relevant acoustic information is effectively suppressed.

Production and Perception of Mandarin Laryngeal Contrast: The Role of Post-plosive F0

This study examines the relation between plosive aspiration and post-plosive f0 (fundamental frequency) in the production and perception of the laryngeal contrast in Mandarin. Production data from 25 Mandarin speakers showed that, in word onsets, VOTs (voice onset time) of aspirated and unaspirated plosives were different, as expected. At the same time, the speakers produced different post-plosive f0 between aspirated and unaspirated plosives, but the difference varied according to the lexical tones – post-aspirated f0 was higher than post-unaspirated f0 in high-initial tones (i.e., lexical tones with high onset f0), but the pattern was the opposite and less robust in low-initial tones. In the perception of the same participants, VOT was the primary cue to aspiration but, when VOT was ambiguous, high post-plosive f0 yielded more aspirated responses in general. We claim that the asymmetry in f0 perturbation between high-initial and low-initial tones in production arises from different laryngeal maneuvers for different tonal targets. In low-initial tones, in which the vocal folds are slack and the glottal opening is wider, aspirated plosives have a lower subglottal air pressure than unaspirated plosives at the voicing onset, resulting in lower post-aspirated f0 than post-unaspirated f0. But in high-initial tones, the vocal folds are tense, which requires a higher trans-glottal pressure threshold to initiate phonation at the onset of voicing. As a result, the subglottal pressure does not decrease as much. Instead, the faster airflow in aspirated than unaspirated plosives gives rise to the pattern that post-aspirated f0 is higher than post-unaspirated f0. Regardless of this variation in production, our perception data suggest that Mandarin listeners generalize the f0 perturbation patterns from high-initial tones and associate high post-plosive f0 with aspirated plosives even in low-initial tone contexts. We cautiously claim that the observed perceptual pattern is consistent with the robustly represented production pattern, as high-initial tones are more prevalent and salient in the language and exhibit stronger f0 perturbation in the speakers' productions.

АКУСТИЧНИ ОСОБЕНОСТИ НА МЕКИ ВЕЛАРНИ СЪГЛАСНИ ОТ ИЗТОЧНОБЪЛГАРСКИ И ЗАПАДНОБЪЛГАРСКИ ТИП / ACOUSTIC FEATURES OF THE SOFT VELAR CONSONANTS OF THE EASTERN BULGARIAN AND THE WESTERN BULGARIAN TYPE

This pilot study discusses the results of the measurement of the acoustic properties of the soft velar plosives [gj] [kj] of the eastern Bulgarian and the western Bulgarian types of articulation in CVC isolated syllables in comparison with the properties of the hard velar plosives [g] and [k] before the vowel [a] and the front vowel [ɛ]. According to the Bulgarian phonetic literature velar consonants preceding front vowels are realized as allophones of the hard consonants, whose articulation and acoustic features are very similar to those of their soft correlates. For the purposes of this study, we chose several acoustic parameters – consonant duration, formant transition duration (F2), F2 onset and F2 offset (Hz), F3 onset and F3 offset (Hz) – and measured them with the Praat software. The main goal is to establish the degree of differentiation between the eastern Bulgarian and the western Bulgarian articulation with respect to velar plosives. The results show that the F2 transition duration is a distinctive feature that sets apart the eastern and the western types of articulation, as well as hard and soft velar plosives. The type of F3 transition can also be considered as a differrentiator between soft and hard velar plosives. The consonant duration could hardly serve to distinguish between the two types of articulation but is relevant for the differentiation of voiced vs. voiceless plosives. Keywords: velar plosives, soft consonants, acoustic measures, Bulgarian, western articulation, eastern articulation

Perceptual Cue Weighting Is Influenced by the Listener's Gender and Subjective Evaluations of the Speaker: The Case of English Stop Voicing.

Speech categories are defined by multiple acoustic dimensions and their boundaries are generally fuzzy and ambiguous in part because listeners often give differential weighting to these cue dimensions during phonetic categorization. This study explored how a listener's perception of a speaker's socio-indexical and personality characteristics influences the listener's perceptual cue weighting. In a matched-guise study, three groups of listeners classified a series of gender-neutral /b/-/p/ continua that vary in VOT and F0 at the onset of the following vowel. Listeners were assigned to one of three prompt conditions (i.e., a visually male talker, a visually female talker, or audio-only) and rated the talker in terms of vocal (and facial, in the visual prompt conditions) gender prototypicality, attractiveness, friendliness, confidence, trustworthiness, and gayness. Male listeners and listeners who saw a male face showed less reliance on VOT compared to listeners in the other conditions. Listeners' visual evaluation of the talker also affected their weighting of VOT and onset F0 cues, although the effects of facial impressions differ depending on the gender of the listener. The results demonstrate that individual differences in perceptual cue weighting are modulated by the listener's gender and his/her subjective evaluation of the talker. These findings lend support for exemplar-based models of speech perception and production where socio-indexical features are encoded as a part of the episodic traces in the listeners' mental lexicon. This study also shed light on the relationship between individual variation in cue weighting and community-level sound change by demonstrating that VOT and onset F0 co-variation in North American English has acquired a certain degree of socio-indexical significance.

The four-way voicing distinction in Bengali infant directed speech

Although vowels in infant-directed Speech (IDS) are thought to be hyper-articulated, findings from consonants are more mixed. Stops in languages with three- and four-way voicing distinctions, in particular, havebeen found to be hypo-articulated in IDS (Narayan and Yoon, 2011—Korean; Benders et al., 2019—Nepali) compared to adult-directed speech (ADS). We investigated the production of stops and affricates in Bengali which has a four-way voicing and aspiration distinction. IDS and ADS samples of connected speech produced by 10 native speakers (5 male and 5 female) of Bangladeshi Bengali (Yu et al., 2014) were compared. Stops and affricates were analyzed for voice onset time, onset f0 and lenition of the closure. Analyses controlled for prosodic position, lexical stress, and speaker sex—variables that are known to influence hypo-articulation. To compare the overlap between categories, acoustic measures were combined to obtain Pillai scores (Hay et al., 2006). Categories with low Pillai scores have more overlap and are thus, less distinct. The implications of the results for acquisition of phonetic categories will be discussed.