Perception of temporal structure in speech is influenced by body movement and individual beat perception ability.

The subjective experience of time flow in speech deviates from the sound acoustics in substantial ways. The present study focuses on the perceptual tendency to regularize time intervals found in speech but not in other types of sounds with a similar temporal structure. We investigate to what extent individual beat perception ability is responsible for perceptual regularization and if the effect can be eliminated through the involvement of body movement during listening. Participants performed a musical beat perception task and compared spoken sentences to their drumbeat-based versions either after passive listening or after listening and moving along with the beat of the sentences. The results show that the interval regularization prevails in listeners with a low beat perception ability performing a passive listening task and is eliminated in an active listening task involving body movement. Body movement also helped to promote a veridical percept of temporal structure in speech at the group level. We suggest that body movement engages an internal timekeeping mechanism, promoting the fidelity of auditory encoding even in sounds of high temporal complexity and irregularity such as natural speech.

Testing an acoustic model of the P-center in English and Japanese.

The notion of the "perceptual center" or the "P-center" has been put forward to account for the repeated finding that acoustic and perceived syllable onsets do not necessarily coincide, at least in the perception of simple monosyllables or disyllables. The magnitude of the discrepancy between acoustics and perception-the location of the P-center in the speech signal- has proven difficult to estimate, though acoustic models of the effect do exist. The present study asks if the P-center effect can be documented in natural connected speech of English and Japanese and examines if an acoustic model that defines the P-center as the moment of the fastest energy change in a syllabic amplitude envelope adequately reflects the P-center in the two languages. A sensorimotor synchronization paradigm was deployed to address the research questions. The results provide evidence for the existence of the P-center effect in speech of both languages while the acoustic P-center model is found to be less applicable to Japanese. Sensorimotor synchronization patterns further suggest that the P-center may reflect perceptual anticipation of a vowel onset.

Towards a Comprehensive Account of Rhythm Processing Issues in Developmental Dyslexia.

Developmental dyslexia is typically defined as a difficulty with an individual's command of written language, arising from deficits in phonological awareness. However, motor entrainment difficulties in non-linguistic synchronization and time-keeping tasks have also been reported. Such findings gave rise to proposals of an underlying rhythm processing deficit in dyslexia, even though to date, evidence for impaired motor entrainment with the rhythm of natural speech is rather scarce, and the role of speech rhythm in phonological awareness is unclear. The present study aimed to fill these gaps. Dyslexic adults and age-matched control participants with variable levels of previous music training completed a series of experimental tasks assessing phoneme processing, rhythm perception, and motor entrainment abilities. In a rhythm entrainment task, participants tapped along to the perceived beat of natural spoken sentences. In a phoneme processing task, participants monitored for sonorant and obstruent phonemes embedded in nonsense strings. Individual sensorimotor skills were assessed using a number of screening tests. The results lacked evidence for a motor impairment or a general motor entrainment difficulty in dyslexia, at least among adult participants of the study. Instead, the results showed that the participants' performance in the phonemic task was predictive of their performance in the rhythmic task, but not vice versa, suggesting that atypical rhythm processing in dyslexia may be the consequence, but not the cause, of dyslexic difficulties with phoneme-level encoding. No evidence for a deficit in the entrainment to the syllable rate in dyslexic adults was found. Rather, metrically weak syllables were significantly less often at the center of rhythmic attention in dyslexic adults as compared to neurotypical controls, with an increased tendency in musically trained participants. This finding could not be explained by an auditory deficit in the processing of acoustic-prosodic cues to the rhythm structure, but it is likely to be related to the well-documented auditory short-term memory issue in dyslexia.

Glasgow Gloom or Leeds Glue? Dialect-Specific Vowel Duration Constrains Lexical Segmentation and Access.

Timing cues are important in many aspects of speech processing, fromidentifying segments to locating word and phrase boundaries. They vary across accents, yet representation and processing of this variation are poorly understood. We investigated whether an accent difference in vowel duration affects lexical segmentation and access. In Glasgow English (GE), /i u e o/ are shorter than in Leeds English (LE), especially for /i u/ before voiced stops and nasals. In a word-spotting experiment, GE and LE participants heard nonsense sequences (e.g. pobegloomezh) containing embedded words (gloom, glue), with segmental qualities intermediate between GE and LE. Critical vowel durations were manipulated according to accent (GE-appropriate vowels shorter than LE-appropriate ones) and phonological context (vowels shortest before voiceless stops < voiced stops/nasals < voiced fricatives). GE participants generally spotted words like gloom more accurately with GE-appropriate than LE-appropriate vowels. LE participants were less accurate than GE participants to spot words like gloom with GE-appropriate vowels, but more likely to spot embeddings like glue. These results were broadly as predicted based on the accent differences, but depended less than expected on the accent-specific phonological constraints. We discuss theoretical implications regarding the representation of duration and the time course of lexical access.

On the Tail of the Scottish Vowel Length Rule in Glasgow.

One of the most famous sound features of Scottish English is the short/long timing alternation of /i u ai/ vowels, which depends on the morpho-phonemic environment, and is known as the Scottish Vowel Length Rule (SVLR). These alternations make the status of vowel quantity in Scottish English (quasi-)phonemic but are also susceptible to change, particularly in situations of intense sustained dialect contact with Anglo-English. Does the SVLR change in Glasgow where dialect contact at the community level is comparably low? The present study sets out to tackle this question, and tests two hypotheses involving (1) external influences due to dialect-contact and (2) internal, prosodically induced factors of sound change. Durational analyses of /i u a/ were conducted on a corpus of spontaneous Glaswegian speech from the 1970s and 2000s; four speaker groups were compared, two of middle-aged men, and two of adolescent boys. Our hypothesis that the development of the SVLR over time may be internally constrained and interact with prosody was largely confirmed. We observed weakening effects in its implementation which were localised in phrase-medial unaccented positions in all speaker groups, and in phrase-final positions in the speakers born after the Second World War. But unlike some other varieties of Scottish or Northern English which show weakening of the Rule under a prolonged contact with Anglo-English, dialect contact seems to be having less impact on the durational patterns in Glaswegian vernacular, probably because of the overall reduced potential for a regular, everyday contact in the West of Scotland.

How Truncating Are 'Truncating Languages'? Evidence from Russian and German.

Russian and German have pr eviously been described as 'truncating', or cutting off target frequencies of the phrase-final pitch trajectories when the time available for voicing is compromised. However, supporting evidence is rare and limited to only a few pitch categories. This paper reports a production study conducted to document pitch adjustments to linguistic materials, in which the amount of voicing available for the realization of a pitch pattern varies from relatively long to extremely short. Productions of nuclear H+L*, H* and L*+H pitch accents followed by a low boundary tone were investigated in the two languages. The results of the study show that speakers of both 'truncating languages' do not utilize truncation exclusively when accommodating to different segmental environments. On the contrary, they employ several strategies - among them is truncation but also compression and temporal re-alignment - to produce the target pitch categories under increasing time pressure. Given that speakers can systematically apply all three adjustment strategies to produce some pitch patterns (H* L% in German and Russian) while not using truncation in others (H+L* L% particularly in Russian), we question the effectiveness of the typological classification of these two languages as 'truncating'. Moreover, the phonetic detail of truncation varies considerably, both across and within the two languages, indicating that truncation cannot be easily modeled as a unified phenomenon. The results further suggest that the phrase-final pitch adjustments are sensitive to the phonological composition of the tonal string and the status of a particular tonal event (associated vs. boundary tone), and do not apply to falling vs. rising pitch contours across the board, as previously put forward for German. Implications for the intonational phonology and prosodic typology are addressed in the discussion.

Speech timing and linguistic rhythm: on the acoustic bases of rhythm typologies.

Research into linguistic rhythm has been dominated by the idea that languages can be classified according to rhythmic templates, amenable to assessment by acoustic measures of vowel and consonant durations. This study tested predictions of two proposals explaining the bases of rhythmic typologies: the Rhythm Class Hypothesis which assumes that the templates arise from an extensive vs a limited use of durational contrasts, and the Control and Compensation Hypothesis which proposes that the templates are rooted in more vs less flexible speech production strategies. Temporal properties of segments, syllables and rhythmic feet were examined in two accents of British English, a "stress-timed" variety from Leeds, and a "syllable-timed" variety spoken by Panjabi-English bilinguals from Bradford. Rhythm metrics were calculated. A perception study confirmed that the speakers of the two varieties differed in their perceived rhythm. The results revealed that both typologies were informative in that to a certain degree, they predicted temporal patterns of the two varieties. None of the metrics tested was capable of adequately reflecting the temporal complexity found in the durational data. These findings contribute to the critical evaluation of the explanatory adequacy of rhythm metrics. Acoustic bases and limitations of the traditional rhythmic typologies are discussed.

When speech sounds like music.

Repetition can boost memory and perception. However, repeating the same stimulus several times in immediate succession also induces intriguing perceptual transformations and illusions. Here, we investigate the Speech to Song Transformation (S2ST), a massed repetition effect in the auditory modality, which crosses the boundaries between language and music. In the S2ST, a phrase repeated several times shifts to being heard as sung. To better understand this unique cross-domain transformation, we examined the perceptual determinants of the S2ST, in particular the role of acoustics. In 2 Experiments, the effects of 2 pitch properties and 3 rhythmic properties on the probability and speed of occurrence of the transformation were examined. Results showed that both pitch and rhythmic properties are key features fostering the transformation. However, some properties proved to be more conducive to the S2ST than others. Stable tonal targets that allowed for the perception of a musical melody led more often and quickly to the S2ST than scalar intervals. Recurring durational contrasts arising from segmental grouping favoring a metrical interpretation of the stimulus also facilitated the S2ST. This was, however, not the case for a regular beat structure within and across repetitions. In addition, individual perceptual abilities allowed to predict the likelihood of the S2ST. Overall, the study demonstrated that repetition enables listeners to reinterpret specific prosodic features of spoken utterances in terms of musical structures. The findings underline a tight link between language and music, but they also reveal important differences in communicative functions of prosodic structure in the 2 domains.