F2 Slope Research Articles

Characterizing the distinctive acoustic cues of Mandarin tones.

This study aims to characterize distinctive acoustic features of Mandarin tones based on a corpus of 1025 monosyllabic words produced by 21 native Mandarin speakers. For each tone, 22 acoustic cues were extracted. Besides standard F0, duration, and intensity measures, further cues were determined by fitting two mathematical functions to the pitch contours. The first function is a parabola, which gives three parameters: a mean F0, an F0 slope, and an F0 second derivative. The second is a broken-line function, which models the contour as a continuous curve consisting of two lines with a single breakpoint. Cohen's d, sparse Principal Component Analysis, and other statistical measures are used to identify which of the cues, and which combinations of the cues, are important for distinguishing each tone from each other among all the speakers. Although the specific cues that best characterize the tone contours depend on the particular tone and the statistical measure used, this paper shows that the three cues obtained by fitting a parabola to the tone contour are broadly effective. This research suggests using these three cues as a canonical choice for defining tone characteristics.

Complex illocutive units in language into act theory

This work presents a preliminary analysis for a prosodic description of two different spoken structures in spoken language within the theoretical framework of the Language into Act Theory (L-AcT): (i) chains of two or more Bound Comments (COB) that do not form a compositional informative and prosodic unit; (ii) compositional Information Units formed by two or more Multiple Comments (CMM) of the List type, linked together by a conventional prosodic model that implements a specific meta-illocutive structure . The goal of this study is to underline specific features of the COB units and the List-type CMM units, detecting prosodic properties of Italian and Brazilian Portuguese spoken language. Through a specific script for Praat software, different parameters are automatically calculated: f0 reset, slope and variation rate, pause duration, spectral emphasis. Our results highlighted a common prosodic behavior in COB-units in terms of f0 movement (rising in the stressed syllable before the break and falling in the unstressed one just before the break), and high similarity between the two COBs and Lists, but also the need to distinguish the effects connected to the position of the stress from the specific features of the unit as detectable Textual Unit.

Relationship Between F2 Slope and Intelligibility in Parkinson's Disease: Lexical Effects and Listening Environment.

Purpose There is a complex relationship between speech production and intelligibility of speech. The current study sought to evaluate the interaction of the factors of lexical characteristics, listening environment, and the 2nd formant transition (F2 slope) on intelligibility of speakers with Parkinson's disease (PD). Method Twelve speakers with PD and 12 healthy controls read sentences that included words with the diphthongs /aɪ/, /ɔɪ/, and /aʊ/. The F2 slope of the diphthong transition was measured and averaged across the 3 diphthongs for each speaker. Young adult listeners transcribed the sentences to assess intelligibility of words with high and low word frequency and high and low neighborhood density in quiet and noisy listening conditions. The average F2 slope and intelligibility scores were entered into regression models to examine their relationship. Results F2 slope was positively related to intelligibility in speakers with PD in both listening conditions with a stronger relationship in noise than in quiet. There was no significant relationship between F2 slope and intelligibility of healthy speakers. In the quiet condition, F2 slope was only correlated with intelligibility in less-frequent words produced by the PD group. In the noise condition, F2 slope was related to intelligibility in high- and low-frequency words and high-density words in PD. Conclusions The relationship between F2 slope and intelligibility in PD was affected by lexical factors and listening conditions. F2 slope was more strongly related to intelligibility in noise than in quiet for speakers with PD. This relationship was absent in highly frequent words presented in quiet and those with fewer lexical neighbors.

Relation of second formant trajectories to tongue kinematics.

In this study, the relationship between the acoustic and articulatory kinematic domains of speech was examined among nine neurologically healthy female speakers using two derived relationships between tongue kinematics and F2 measurements: (1) second formant frequency (F2) extent to lingual displacement and (2) F2 slope to lingual speed. Additionally, the relationships between these paired parameters were examined within conversational, more clear, and less clear speaking modes. In general, the findings of the study support a strong correlation for both sets of paired parameters. In addition, the data showed significant changes in articulatory behaviors across speaking modes including the magnitude of tongue motion, but not in the speed-related measures.

/l/ velarisation as a continuum.

In this paper, we present a production study to explore the controversial question about /l/ velarisation. Measurements of first (F1), second (F2) and third (F3) formant frequencies and the slope of F2 were analysed to clarify the /l/ velarisation behaviour in European Portuguese (EP). The acoustic data were collected from ten EP speakers, producing trisyllabic words with paroxytone stress pattern, with the liquid consonant at the middle of the word in onset, complex onset and coda positions. Results suggested that /l/ is produced on a continuum in EP. The consistently low F2 indicates that /l/ is velarised in all syllable positions, but variation especially in F1 and F3 revealed that /l/ could be “more velarised” or “less velarised” dependent on syllable positions and vowel contexts. These findings suggest that it is important to consider different acoustic measures to better understand /l/ velarisation in EP.

Interaction Between Pitch and Timbre Perception in Normal-Hearing Listeners and Cochlear Implant Users.

Despite their mutually exclusive definitions, pitch and timbre perception interact with each other in normal-hearing (NH) listeners. Cochlear implant (CI) users have worse than normal pitch and timbre perception. However, the pitch-timbre interaction with CIs is not well understood. This study tested the interaction between pitch and sharpness (an aspect of timbre) perception related to the fundamental frequency (F0) and spectral slope of harmonic complex tones, respectively, in both NH listeners and CI users. In experiment 1, the F0 (and spectral slope) difference limens (DLs) were measured with a fixed spectral slope (and F0) and 20-dB amplitude roving. Then, the F0 and spectral slope were varied congruently or incongruently by the same multiple of individual DLs to assess the pitch and sharpness ranking sensitivity. Both NH and CI subjects had significantly higher pitch and sharpness ranking sensitivity with congruent than with incongruent F0 and spectral slope variations, and showed a similar symmetric interaction between pitch and timbre perception. In experiment 2, CI users' melodic contour identification (MCI) was tested in three spectral slope (no, congruent, and incongruent spectral slope variations by the same multiple of individual DLs as the F0 variations) and two amplitude conditions (0- and 20-dB amplitude roving). When there was no amplitude roving, the MCI scores were significantly higher with congruent than with no, and in turn than with incongruent spectral slope variations. The 20-dB amplitude roving significantly reduced the overall MCI scores and the effect of spectral slope variations. These results reflected a confusion between higher (or lower) pitch and sharper (or duller) timbre and offered important implications for understanding and enhancing pitch and timbre perception with CIs.

Identifying the distinctive acoustic cues of Mandarin tones

Using mathematical modeling, this study aims to characterize distinctive acoustic features of Mandarin tones based on a corpus of 1013 monosyllabic words produced by 21 native Mandarin speakers. For each tone, 22 acoustic cues were extracted. Besides standard F0, duration, and intensity measures, further cues were determined by fitting two mathematical models to the pitch contours. The first is a broken-line model, which models the contour as a continuous curve consisting of two lines with a single breakpoint. The second model is a parabola, which gives three parameters: a mean F0, an F0 slope, and an F0 curvature. Using Cohen’s d, we identify which of the 22 cues are important for distinguishing each tone from the others for all speakers, as well as identifying cues that are used idiosyncratically by particular speakers. Although the specific cues that best characterize each tone differ, we show that the three cues obtained by fitting a parabola to the tone contour are an effective small set of cues such that any pair of tones is well distinguished by at least one of them. We propose using these three cues as a canonical choice for defining tone characteristics.

Diphthong productions in speakers with Parkinson’s disease across speaking modes

Several vowel acoustics parameters (e.g., second formant frequency (F2) slope, vowel space area) are known to significantly contribute to speech intelligibility in dysarthria (Kim, Kent, Weismer, 2011; Lansford & Liss, 2014). Particularly, F2 slope has been identified as an important predictor of speech intelligibility regardless of underlying neuropathologies of dysarthria (Kim, Weismer, Kent & Duffy, 2009). The current study focuses on intra-speaker modifications of F2 slope in speakers with Parkinson’s disease (PD) voluntarily elicited across three speaking modes, less clear, conversational, and more clear speech, in recognition that prior work has mostly focused on inter-speaker comparisons. Varying speech clarity was our interest, given its wide use as an efficient behavioral therapeutic approach in clinic. Twenty speakers (10 PD, 10 neurologically healthy) were asked to read diphthongs embedded in real words. Diphthongs were chosen because they require a significant change in configuration of vocal tract and, therefore, are sensitive to the presence/severity of dysarthria. In the presentation, distributions of F2 slope 1) between PD and healthy speakers, and 2) across speaking modes within each speaker will be discussed. In addition, articulatory data will be presented for part of the speakers from whom kinematic data were obtained using the electromagnetic articulography (EMA) system.

Neutralization of underlying vs. derived “unnatural” palatals in Xhosa

Xhosa (Bantu) has an “unnatural” process of palatalization—contrary to typological expectations, it is triggered by [w], but not [i] or [j], and applies only to labials. For example, [m]→[ɲ] as in uku-lum-a to bite' ~ uku-luɲ-w-a ‘to be bitten', and [mb]→[ⁿdʒ] as in uku-ɬamb-a 'to wash' ~ uku-ɬaⁿdʒ-w-a ‘to be washed'. This paper compares underlying and derived palatals to determine whether the palatal/non-palatal contrast is neutralized (in)completely in the derivational context. 40 Xhosa nonce verbs, ending in segments which undergo palatalization, were created to be read by 6 native speakers. Speakers read these forms and were then asked to produce forms with the passive -w suffix, thus triggering palatalization. F2 was measured at boundaries and ten ms. into the vowels preceding and following the palatalized segment. F2 at ten ms into the following vowel differed on average by 167.99 Hz between underlying and derived palatals, trending towards, but not reaching significance (t = 1.94, p = 0.054), while F2 slope showed no clear trend. While Zsiga (1995) proposes that English palatalization can be complete or gradient, this is the first study of palatalization in the context of incomplete neutralization, and the first study to look at incomplete neutralization in Bantu.Xhosa (Bantu) has an “unnatural” process of palatalization—contrary to typological expectations, it is triggered by [w], but not [i] or [j], and applies only to labials. For example, [m]→[ɲ] as in uku-lum-a to bite' ~ uku-luɲ-w-a ‘to be bitten', and [mb]→[ⁿdʒ] as in uku-ɬamb-a 'to wash' ~ uku-ɬaⁿdʒ-w-a ‘to be washed'. This paper compares underlying and derived palatals to determine whether the palatal/non-palatal contrast is neutralized (in)completely in the derivational context. 40 Xhosa nonce verbs, ending in segments which undergo palatalization, were created to be read by 6 native speakers. Speakers read these forms and were then asked to produce forms with the passive -w suffix, thus triggering palatalization. F2 was measured at boundaries and ten ms. into the vowels preceding and following the palatalized segment. F2 at ten ms into the following vowel differed on average by 167.99 Hz between underlying and derived palatals, trending towards, but not reaching significance (t = 1.94, p = 0.054), whi...

Do Hindi speakers of English realize the acoustic cues for American English /v/ and /w/ contrast?

The Hindi phonological inventory does not include a [v-w] contrast. In a perception study, Hindi speakers identified /v/ and /w/ in American English (AE) words with approximately 50% accuracy (Grover et al., 2016). The present study compares AE /v/ and /w/ productions in bilingual Hindi-English speakers’ with those of AE speakers’ in nonsense words. Two AE listeners annotated recordings of word-initial and word-medial tokens to label F2 onset and presence of frication. F2 onset frequency and F2 slope were calculated. Hindi speakers were divided into two groups, those with length of residence (LOR) in the US of more than five years, and those who reside in India. Results revealed a significant difference between the AE group and both Hindi groups for F2 onset frequency and F2 slope. There was no significant difference between Hindi groups. The AE group had frication for /v/ tokens, but not for /w/. Both Hindi groups produced frication at about the same rate for /v/ and /w/. The finding of no significant difference between the Hindi groups indicates that exposure to the /v/-/w/ contrast in the US did not improve Hindi speakers’ production. This further indicates a need to design targeted training for this contrast.

Vocalic transitions as markers of speech acoustic changes with STN-DBS in Parkinson’s Disease

PurposeDeep Brain Stimulation of the subthalamic nucleus (STN-DBS) effectively treats cardinal symptoms of idiopathic Parkinson’s disease (PD) that cannot be satisfactorily managed with medication. Research is equivocal regarding speech changes associated with STN-DBS. This study investigated the impact of STN-DBS on vocalic transitions and the relationship to intelligibility. MethodsEight Quebec-French speakers with PD and eight healthy controls participated. The slope of the second formant frequency (F2 slope) for glides was obtained. Locus equations (LEs) were calculated to capture vocalic transitions in consonant-vowel sequences. A visual analog scale was used to obtain judgments of intelligibility. Measures for the PD group were obtained both On and Off stimulation. ResultsF2 slopes and LEs differed among groups, but there were no systematic differences for On versus Off STN-DBS. On an individual level, participants with PD exhibited heterogeneous changes with DBS stimulation. Intelligibility was significantly correlated with F2 slope. ConclusionF2 slope appears to be sensitive to articulatory impairment in PD and could be used in clinical settings to distinguish these speakers from healthy controls. However, acoustic metrics failed to identify systematic change with STN-DBS. The heterogeneity of results, as well as the clinical relevance of acoustic metrics are discussed.

Acoustic consequences of speech treatment in children with cerebral palsy

Cerebral palsy (CP) is the most common motor disability in childhood and can severely impact speech intelligibility. However, sparse evidence exists on which to base treatment. The current study examined the acoustic outcomes of Speech-Systems-Intelligibility-Treatment (Levy, 2014), a speech treatment aimed at enhancing intelligibility by targeting increased articulatory-working-space and vocal intensity through child-friendly prompts. Thirteen American-English speaking children with spastic dysarthria due to CP were assigned to a speech treatment group or a control group. Before and after treatment, participants repeated pre-recorded minimal pair nonsense words contrasting only in the initial consonant. Acoustic analysis of the children’s nonsense word productions indicated that on average, duration and sound-pressure-level (SPL) increased for the speech group post-treatment. Similar increases were observed in the control group’s SPL and duration, but to a lesser extent. Thus, preliminary results suggest promising treatment effects on speech acoustics for repeated words. Analyses of fricative-affricate contrasts, and F2 slope changes shed additional light on stability and changes in the speech of children with dysarthria in response to treatment. Additionally, changes in connected speech without a model talker may point to possible transfer of new skills to more spontaneous speech.

Differentiating infant cry from non-cry vocalizations based on perception of negativity and acoustic features

This study seeks to determine how human listeners discriminate cry vs. non-cry sounds by investigating acoustic factors that may contribute to the perception of negativity in infant vocalizations (e.g., cry, whine, and vowel-like sounds). The assumption is that identification of cry is self-evident; therefore, there has been no attempt to systematically differentiate cry from non-cry vocalizations. Twelve exemplars each of cry, whine, and vowel-like sound segments (36 total) were selected from archival audio recordings of infant vocalizations. Categories were selected from expert-judged audio signals of vocal development. Adult listeners identified each utterance as either cry, whine, or vowel-like sound as quickly and accurately as possible. They also judged the extent of negativity of each utterance. Acoustic features of each utterance were analyzed in association with the categories and degrees of negativity. Results suggest a continuum of negativity from cries (most negative) to vowel-like sounds (least negative), and that acoustic variables are gradated across the negativity continuum. However, preliminary results suggest that peak F0, peak RMS, and spectral slope best differentiate the categories.

Allophonic tunes of contrast: Lab and spontaneous speech lead to equivalent fixation responses in museum visitors

A prominent pitch accent is known to trigger immediate contrastive interpretation of the accented referential expression. Previous experimental demonstrations of this effect, where [L+H* unaccented] contours led to an increase in earlier responses than [H* !H*] contours in contrastive context, may have benefited from the use of laboratory speech with stylized, homogenous pitch contours as well as data collected from a uniform participant group—college students. The present study tested visitors to a science museum, who better represent the general public, comparing lab and spontaneous speech to replicate the contrast-evoking effect of prominent pitch accent. Across two eye-tracking experiments where participants followed spoken instructions to decorate Christmas trees, spontaneous two-word [L+H* unaccented] contours led to faster eye-movements to contrastive ornament sets than [H* !H*] contours with no delay as compared to lab speech. The differences in the fixation functions were overall smaller than those in a previous study that used clear lab speech in richer contexts. Detailed acoustic analyses indicated that the lab speech tune types were distinguishable by any of several independent F0 measures on the adjective and by F0 slope. In contrast, no single phonetic measure on the spontaneous speech adjective distinguished between tune types, which were best classified according to independent noun-based measures. However, a non-linear combination of the adjective measures was shown to be equal to the noun measures in distinguishing between the [H* !H*] and [L+H* unaccented] tunes. The eye-movement data suggest that naive listeners were comparably sensitive to both lab and spontaneous prosodic cues on the adjective and made anticipatory eye-movements accordingly.

The Interaction of Lexical Characteristics and Speech Production in Parkinson's Disease.

This study sought to investigate the interaction of speech movement execution with higher order lexical parameters. The authors examined how lexical characteristics affect speech output in individuals with Parkinson's disease (PD) and healthy control (HC) speakers. Twenty speakers with PD and 12 healthy speakers read sentences with target words that varied in word frequency and neighborhood density. The formant transitions (F2 slopes) of the diphthongs in the target words were compared across lexical categories between PD and HC groups. Both groups of speakers produced steeper F2 slopes for the diphthongs in less frequent words and words from sparse neighborhoods. The magnitude of the increase in F2 slopes was significantly less in the PD than HC group. The lexical effect on the F2 slope differed among the diphthongs and between the 2 groups. PD and healthy speakers varied their acoustic output on the basis of word frequency and neighborhood density. F2 slope variations can be traced to higher level lexical differences. This lexical effect on articulation, however, appears to be constrained by PD.

The effect of jaw position on perceptual and acoustic characteristics of speech

Bite blocks are used to stabilize the jaw and to isolate tongue and lip movements from that of the mandible during speech and nonspeech activities. Ten normally speaking young adults produced sentences with an unconstrained jaw and with unilateral placement of 2-mm and 5-mm bite blocks. Six listeners rated sentences spoken without either bite block as the most natural sounding. Spectral characteristics of /s/, /J/ and /t/ (sibilant frication and stop bursts) differed significantly with than without bite blocks, such that mean spectral energy decreased, and variation and skew of spectral energy increased. Spectral kurtosis did not change for the group, but 2 participants exhibited highly kurtotic /s/ spectra without a bite block that normalized with bite blocks. The second formant frequency for the high vowel /i/ was lower with bite blocks; there was no systematic difference in F2 slope for diphthongs. Segmental and suprasegmental timing of speech articulation was not affected significantly by these small bite blocks. This study provides support for using small bite blocks to isolate the tongue from the jaw without large effects on speech, but cautions that speech is likely to sound less natural than when produced with an unconstrained jaw.

An acoustic and perceptual evaluation of four historic recordings of Chinese narrative singing

This study is an acoustic and perceptual musicological evaluation of four recordings of vocal renditions from two schools of Chinese narrative singing that were differentiated by gender during the first half of the twentieth century. The analyses were based on four renditions of “At Break of Day” by Liu Baoquan (1869-1942) and Xiao Lanyun (1923-1992) of the “male school”, as well as Luo Yusheng (1914-2002) and Lu Yiqin (1933-) of the “female school.” The musicological analysis was based on transcriptions of the recordings, comparing melody, rhythm, ornamentation, and tonality. The acoustic analyses involved measures of central tendency and variability for duration and fundamental frequency (F0) using Praat acoustic analysis software. All four vocalists exhibited a similar mean F0, however differences in relative duration, F0 range, F0 variation, and F0 slope were found across singers at both the phrase and syllable level. Differences within schools of singing (male and female) and between instructor and student (i.e., Liu Baoquan and Xiao Lanyun) were also noted. These acoustic differences provide additional insights for ethnomusicologists that may be unattainable through traditional methods of perceptual analysis.

F2 slope as a Perceptual Cue for the Front-Back Contrast in Standard Southern British English.

Acoustic studies of several languages indicate that second-formant (F2) slopes in high vowels have opposing directions (independent of consonantal context): front [iː]-like vowels are produced with a rising F2 slope, whereas back [uː]-like vowels are produced with a falling F2 slope. The present study first reports acoustic measurements that confirm this pattern for the English variety of Standard Southern British English (SSBE), where /uː/ has shifted from the back to the front area of the vowel space and is now realized with higher midpoint F2 values than several decades ago. Subsequently, we test whether the direction of F2 slope also serves as a reliable cue to the /iː/-/uː/ contrast in perception. The findings show that F2 slope direction is used as a cue (additional to midpoint formant values) to distinguish /iː/ from /uː/ by both young and older Standard Southern British English listeners: an otherwise ambiguous token is identified as /iː/ if it has a rising F2 slope and as /uː/ if it has a falling F2 slope. Furthermore, our results indicate that listeners generalize their reliance on F2 slope to other contrasts, namely /ɛ/-/ɒ/ and /æ/-/ɒ/, even though F2 slope is not employed to differentiate these vowels in production. This suggests that in Standard Southern British English, a rising F2 seems to be perceptually associated with an abstract feature such as [+front], whereas a falling F2 with an abstract feature such as [-front].

Formant transitions in the fluent speech of Farsi-speaking people who stutter

PurposeSecond formant (F2) transitions can be used to infer attributes of articulatory transitions. This study compared formant transitions during fluent speech segments of Farsi (Persian) speaking people who stutter and normally fluent Farsi speakers. MethodsTen Iranian males who stutter and 10 normally fluent Iranian males participated. Sixteen different “CVt” tokens were embedded within the phrase “Begu CVt an”. Measures included overall F2 transition frequency extents, durations, and derived overall slopes, initial F2 transition slopes at 30ms and 60ms, and speaking rate. Results(1) Mean overall formant frequency extent was significantly greater in 14 of the 16 CVt tokens for the group of stuttering speakers. (2) Stuttering speakers exhibited significantly longer overall F2 transitions for all 16 tokens compared to the nonstuttering speakers. (3) The overall F2 slopes were similar between the two groups. (4) The stuttering speakers exhibited significantly greater initial F2 transition slopes (positive or negative) for five of the 16 tokens at 30ms and six of the 16 tokens at 60ms. (5) The stuttering group produced a slower syllable rate than the non-stuttering group. ConclusionsDuring perceptually fluent utterances, the stuttering speakers had greater F2 frequency extents during transitions, took longer to reach vowel steady state, exhibited some evidence of steeper slopes at the beginning of transitions, had overall similar F2 formant slopes, and had slower speaking rates compared to nonstuttering speakers. Findings support the notion of different speech motor timing strategies in stuttering speakers. Findings are likely to be independent of the language spoken.Educational objectives This study compares aspects of F2 formant transitions between 10 stuttering and 10 nonstuttering speakers. Readers will be able to describe: (a) characteristics of formant frequency as a specific acoustic feature used to infer speech movements in stuttering and nonstuttering speakers, (b) two methods of measuring second formant (F2) transitions: the visual criteria method and fixed time criteria method, (c) characteristics of F2 transitions in the fluent speech of stuttering speakers and how those characteristics appear to differ from normally fluent speakers, and (d) possible cross-linguistic effects on acoustic analyses of stuttering.

Acoustic Characteristics of the Korean Diphthongs of Children from Korean-Vietnamese Multi-cultural Environment Focusing on the F2 Slope

Acoustic Characteristics of the Korean Diphthongs of Children from Korean-Vietnamese Multi-cultural Environment Focusing on the F2 Slope