The relation among fundamental frequency, intensity, and duration varies with accentuation

Lexical Segmentation in Artificial Word Learning: The Effects of Converging Sublexical Cues

This study examines how French listeners segment and learn new words of artificial languages varying in the presence of different combinations of sublexical segmentation cues. The first experiment investigated the contribution of three different types of sublexical cues (acoustic-phonetic, phonological and prosodic cues) to word learning. The second experiment explored how participants specifically exploited sublexical prosodic cues. Whereas complementary cues signaling word-initial and word-final boundaries had synergistic effects on word learning in the first experiment, the two manipulated prosodic cues redundantly signaling word-final boundaries in the second experiment were rank-ordered with final pitch variations being more weighted than final lengthening. These results are discussed in light of the notions of cue type, cue position and cue efficiency.

Relations among subglottal pressure, breathing, and acoustic parameters of sentence-level prominence in German

This study investigates whether acoustic correlates of prominence are related to actions of the respiratory system resulting in local changes of subglottal pressure (Psub). Simultaneous recordings were made of acoustics; intraoral pressure (Pio), as an estimate of Psub; and thoracic and abdominal volume changes. Ten German speakers read sentences containing a verb ending with /t/ followed by a noun starting with /t/. These /t#t/ sequences were typically realized as one /t:/ with a long intraoral pressure plateau. Sentence-level prominence was manipulated by shifting the position of contrastive focus within the sentences. The slope and peak values of Pio within the /t#t/ sequence were used to estimate differences in Psub across focus positions. Results show that prominence production is related to changes in the slope and maximum value of the pressure plateau. While pressure increases led to higher intensity, the increases did not relate to f0, hence, suggesting that local f0 changes primarily reflect laryngeal activity. Finally, strong individual differences were observed in the respiratory data. These findings confirm past reports of local Psub increases corresponding to sentence-level prominence. Speaker-specific activations of the respiratory system are interpreted in terms of motor equivalence, with laryngeal mechanisms also appearing to contribute to Psub changes.

Evidence for impaired sound intensity processing in schizophrenia

Patients with schizophrenia are impaired in many aspects of auditory processing, but indirect evidence suggests that intensity perception is intact. However, because the extraction of meaning from dynamic intensity relies on structures that appear to be altered in schizophrenia, we hypothesized that the perception of auditory looming is impaired as well. Twenty inpatients with schizophrenia and 20 control participants, matched for age, gender, and education, gave intensity ratings of rising (looming) and falling intensity sounds with different mean intensities. Intensity change was overestimated in looming as compared with receding sounds in both groups. However, healthy individuals showed a stronger effect at higher mean intensity, in keeping with previous findings, while patients with schizophrenia lacked this modulation. We discuss how this might support the notion of a more general deficit in extracting emotional meaning from different sensory cues, including intensity and pitch.

Effects of simultaneous perturbations of voice pitch and loudness feedback on voice F0 and amplitude control

Perturbations in either voice pitch or loudness feedback lead to changes in a speaker's voice fundamental frequency (F0) or amplitude. Voice pitch or loudness perturbations were presented individually (either pitch or loudness shift stimuli) or simultaneously (pitch combined with loudness shift stimuli) to subjects sustaining a vowel to test the hypothesis that the mechanisms for these two response types are independent. For simultaneous perturbations, pitch and loudness both changed in the same direction or in opposite directions. Results showed that subjects responded with voice F0 or amplitude responses that opposed the direction of the respective pitch- or loudness shift stimuli. Thus, depending on the stimulus direction, both responses could either change in the same direction or in the opposite direction to each other. F0 response magnitudes were greatest with pitch-shift only stimuli (18 cents), smallest for loudness shift stimuli (10 cents) and intermediate with pitch combined with loudness shift stimuli (13 and 16 cents). Amplitude responses were largest with +3 dB stimuli (0.96 dB) and smallest with -3 dB stimuli (0.49 dB) but were not affected by the addition of pitch-shift stimuli. Results suggest the F0 and amplitude response mechanisms may be independent but interact in some conditions.

Voice F0 responses to pitch-shifted voice feedback during English speech

Previous studies have demonstrated that motor control of segmental features of speech rely to some extent on sensory feedback. Control of voice fundamental frequency (F0) has been shown to be modulated by perturbations in voice pitch feedback during various phonatory tasks and in Mandarin speech. The present study was designed to determine if voice Fo is modulated in a task-dependent manner during production of suprasegmental features of English speech. English speakers received pitch-modulated voice feedback (+/-50, 100, and 200 cents, 200 ms duration) during a sustained vowel task and a speech task. Response magnitudes during speech (mean 31.5 cents) were larger than during the vowels (mean 21.6 cents), response magnitudes increased as a function of stimulus magnitude during speech but not vowels, and responses to downward pitch-shift stimuli were larger than those to upward stimuli. Response latencies were shorter in speech (mean 122 ms) compared to vowels (mean 154 ms). These findings support previous research suggesting the audio vocal system is involved in the control of suprasegmental features of English speech by correcting for errors between voice pitch feedback and the desired F0.

The Doppler effect is not what you think it is: dramatic pitch change due to dynamic intensity change

Historically, auditory pitch has been considered to be a function of acoustic frequency, with only a small effect being due to absolute intensity. Yet we found that when tones are Doppler shifted so that frequency drops, the pitch dramatically rises and falls, closely following the pattern of dynamic intensity change. We show that continuous intensity change can produce pitch variation comparable to a frequency change approaching an octave. This effect opposes and is an order of magnitude larger than the well-known effect of discrete intensity change in the frequency range employed. We propose that the perceptual interaction of continuous changes in pitch and loudness reflects a natural correlation between changes in frequency and intensity that is neurally encoded to facilitate the parsing and processing of meaningful acoustic patterns.

The ability to effect intended stress following traumatic brain injury

This study was designed to explore the production of word stress following traumatic brain injury (TBI). Ten subjects with TBI and ten matched normal controls produced a sentence with stress elicited on different words. The difference between stressed and unstressed productions of the same word was calculated for intensity, fundamental frequency and duration. Subject's intensity range, fundamental frequency range and vital capacity were also obtained. Naive listeners judged which word was stressed within each sentence. Individuals with TBI were significantly less accurate conveying intended stress compared with normal controls. Individuals with TBI produced significantly less difference in duration between stressed and unstressed words. There was no correlation for either group between percentage change in intensity, fundamental frequency, or duration and the related physiological range. Durational control requires subtle physiological adjustments that individuals with TBI may be unable to accomplish. Further, compensatory strategies may place excessive cognitive demands on the speaker. Thus, the production of stress contrasts may not be amenable to therapeutic intervention. Rather, listeners may be required to rely on context to infer intended stress.