Fine gradations of prosodic boundary strength can drive the assignment of prominence

We know that post-lexical stress shift is blocked when two words with abutting main prominences (e.g., afternoon and hike) are separated by Intonational Phrase (IP) boundaries. However, when the clashing words belong to the same IP (e.g., afternoon hike), we do not know whether the shift can also be obstructed by finer gradations of prosodic boundary strength, below the IP level. This paper reports on an experiment manipulating prosodic boundary strength via constituent length variations. Twenty-nine speakers produced in context 28 pairs of potentially clashing sequences (e.g., canteen soup vs. canteen supervisor), where Word 2 was one syllable (e.g., soup, Short condition designed to elicit weaker prosodic boundaries) or four syllables long (e.g., supervisor, Long condition to elicit stronger boundaries). The length manipulation affected the stress shift rate, which was higher in the Short condition. The acoustic analyses show significant changes of syllable duration, f0 and SPL in both syllables of the target. The results provide evidence that the grouping within one IP of clashing words is not sufficient condition for stress shift to take place, as the shift can be obstructed by gradations in prosodic boundary strength between the clashing words, even if they belong to the same IP

Phrasal Prominence Location is Influenced by IP Boundary Location in the Absence of Stress Clash

Several factors can influence early prominence in double-stressed words (e.g., Maltese), namely the presence of foot-level stress clash with a following word, and their adjacency to domain-initial boundaries. We test whether initial accent can occur in such words even when the words are spoken in isolation. Fourteen targets and 26 tri-syllabic filler-items were produced in isolation and in a frame sentence, e.g., [Say Maltese again], by 12 English speakers. In isolation, ‘Early’ prominence on, e.g., Mal- is more likely because the target is utterance- and phrase-initial. In the Embedded condition, phrasal prominence should be less likely on the initial syllable because there is a weaker boundary preceding the target. Three linguists coded prominence location. Early prominence rates, and Early scores (sum of ‘Early’ judgements/token) were calculated. While 96% of the Embedded tokens were perceived with ‘Late’ prominence, this pattern appeared in only 48% of the Isolated targets. The Early scoreswere also significantly higher in the Isolated condition. Overall, results suggest that doubly-stressed words show stress shifting to demarcate the left IP-edge. Because this study uses contexts free of stress clash with a following word, its results provide evidence that other factors, namely domain-onset-marking, can influence prominence location

Optimization-based modeling of Lombard speech articulation:Supraglottal characteristics

This paper shows that a highly simplified model of speech production based on the optimization of articulatory effort versus intelligibility can account for some observed articulatory consequences of signal-to-noise ratio. Simulations of static vowels in the presence of various background noise levels show that the model predicts articulatory and acoustic modifications of the type observed in Lombard speech. These features were obtained only when the constraint applied to articulatory effort decreases as the level of background noise increases. These results support the hypothesis that Lombard speech is listener oriented and speakers adapt their articulation in noisy environments.</p

Optimal control of speech with context-dependent articulatory targets

This paper presents a computational implementation of phonetic planning which consists of choosing the position of articulatory targets which satisfy conflicting linguistic and extra-linguistic requirements. We present a minimal model that considers intelligibility and least effort as task requirements. To achieve the context-dependent variability of targets, our model approximates intelligibility as a function of target phoneme recognition probability given a vector of articulatory parameters. Preliminary experiments show that our minimal computational model of phonetic planning is able to predict two types of hypoarticulation by adjusting the weight assigned to effort: vowel centralization and stop consonant lenition.Peer reviewe

The American English Flapping Rule and the Effect of Stress on Stop Consonant Durations

The experiment described in this paper concerns the American English Flapping Rule, whereby non-ward-initial iintervocalic /t/ and /d/ are flapped when preceding an unstressed vowel, as in the words 'metal' and 'pyramidal'; in contrast the /t/ preceding a stressed vowel in 'metallic' is not flapped. Acoustically, a major difference between flapped and non-flapped alveolars is durational: flaps are considerably shorter than their non-flapped counterparts. In this study we measured the durations of intervocalic stops in both the non-flapping and flapping environments as well as the durations of vowels that preceded the alveolars in order to answer the following questions: 1. Does a general timing mechanism underly the rule? It may be the case that the extreme shortening found in /t/ and /d/ is an instantiation of a more general timing principle. We discuss possible mechanisms far the length differences between poststress and prestress stops as well as implications for the formulation of the American English flapping rule. 2. Are vowels preceding flaps that were underlying /d/'s longer than vowels preceding flaps that were underlying /t/'s? It is well-known that vowels preceding voiced stops tend to be longer than vowels preceding voiceless stops (e.g. Chen, 1970). Longer vowels before flapped /d/'s than before flapped /t/'s would suggest that lengthening before voiced segments is due to the underlying phonological distinction ([+voice] vs. [-voice]) rather than to the phonetic realization of the consonant (which, in the case of most flaps, is as a voiced segment). In fact, one study (Fox and Terbeek, 1977) found that vowels preceding flapped /d/'s were longer than vowels preceeding flapped /t/'s. 3. Does a longer phonological phrase affect segment durations?This paper is copyrighted, and is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) - see https://creativecommons.org/licenses/by-nc-nd/4.0