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Prosodic structure and syntactic structure are not identical; neither are they unrelated. Knowing when and how the two correspond could yield better quality speech synthesis, could aid in the disambiguation of competing syntactic hypotheses in speech understanding, and could lead to a more comprehensive view of human speech processing. In a set of experiments involving 35 pairs of phonetically similar sentences representing seven types of structural contrasts, the perceptual evidence shows that some, but not all, of the pairs can be disambiguated on the basis of prosodic differences. The phonological evidence relates the disambiguation primarily to boundary phenomena, although prominences sometimes play a role. Finally, phonetic analyses describing the attributes of these phonological markers indicate the importance of both absolute and relative measures. [ABSTRACT FROM AUTHOR]

Serial ordering errors in spontaneous speech often involve individual phoneme-like segments, but seldom larger syllabic components containing both consonants and vowels. This observation suggests that syllabic structure provides a framework for the serial ordering of individual phonemic segments, while larger subsyllabic units and entire syllables do not themselves undergo such ordering during normal production planning (Shattuck-Hufnagel 1979; Shattuck-Hufnagel and Klatt 1979). When speakers repeated syllable sequences constructed by alternating pairs of consonants in conflicting patterns (e.g., PAN FILL FUN POLL, where initial /p, f/ alternate in the pattern ABBA, final /n, l/ in ABAB), 95% of the errors involved a change in a single segment and only 5% involved a CV, VC, or CVC unit. These findings support the view that speech production planning involves the serial ordering of phoneme-like segments, and not of larger syllabic components. Further questions about the nature of position constraints on segments interacting in errors, and about the role of word stress in constraining single-segment errors, are also being explored using this method. [ABSTRACT FROM AUTHOR]

Prosody consists of that information in speech which can be suprasegmental, i.e., operate over units larger than a single segment. Prosodic contours may span a word, phrase, or larger units. The goal of this study is to understand the mapping between discrete, abstract units (e.g., boundary tones, pitch accents) and their observed continuously varying acoustic correlates (e.g., duration and F0). Since prosody synthesis and analysis have traditionally been a challenging problem, the initial focus of this study has been restricted to the FM radio news broadcasting style of speech. This pilot study indicates that in this speech style, prosodic units appear to be more strongly and more regularly marked than in conversational styles. Time- and pitch-scale modification is employed using a sinusoidal model to change the duration and F0 contours of natural utterances. This technique allows synthesis of an utterance with a new prosodic contour, taking the input parameters from a linguistic model of prosody, or from another utterance with different phrasing. In this way, the perceptual effectiveness of various models in marking prosodic prominences and boundaries can be explored. The details of the method will be discussed, and a sample tape will be played. [ABSTRACT FROM AUTHOR]

Fifteen hundred phonetic substitution errors were collected from spontaneous conversations of adult native speakers of English and formed into a confusion matrix of target versus intrusion phonemes. The matrix was analyzed using several methods for evidence of distinctive feature constraints on substitution patterns. Results are compared with evidence from studies of phoneme confusions in perception and in short-term memory. For many features, a substitution in the consonant matrix is significantly more likely to preserve the feature value of the target than would be expected by chance, suggesting that at some point in the production process, segments are represented psychologically in terms of features. The matrix formed by vowel substitutions, although smaller, also supports a traditional feature analysis, but the distinction between front and back vowels is often lost in substitutions. Other constraints which emerge from the error matrix include a sharp distinction between consonants and vowels, and little support for a strictly binary feature system. [ABSTRACT FROM AUTHOR]

Two types of consonant gemination characterize Italian: lexical and syntactic. Italian lexical gemination is contrastive, so that two words may differ by only one geminated consonant. In contrast, syntactic gemination occurs across word boundaries and affects the initial consonant of a word in specific contexts, such as the presence of a monosyllabic morpheme before the word. This study investigates the acoustic correlates of Italian lexical and syntactic gemination, asking if the correlates for the two types are similar in the case of stop consonants. Results confirmed previous studies showing that duration is a prominent gemination cue, with a lengthened consonant closure and a shortened pre-consonant vowel for both types. Results also revealed the presence, in about 10%-12% of instances, of a double stop-release burst, providing strong support for the biphonematic nature of Italian geminated stop consonants. Moreover, the timing of these bursts suggests a different planning process for lexical vs syntactic geminates. The second burst, when present, is accommodated within the closure interval in syntactic geminates, while lexical geminates are lengthened by the extra burst. This suggests that syntactic gemination occurs during a post-lexical phase of production planning, after timing has already been established.

This study examines the acoustic realizations of American English intervocalic flaps in the TIMIT corpus, using the landmark-critical feature-cue-based framework. Three different acoustic patterns of flaps are described: (i) both closure and release landmarks present, (ii) only the closure landmark present, and (iii) both landmarks deleted. The patterns occur consistently across several phonological and morphological conditions but vary with sociolinguistic factors, including speaker dialect and gender. This method of analysing speech at the level of acoustic landmarks and other individual cues to distinctive features contributes to a deeper understanding of how speakers and listeners employ systematic variation in phonetic detail in speech processing.

Acoustic cues are characteristic patterns in the speech signal that provide lexical, prosodic, or additional information, such as speaker identity. In particular, acoustic cues related to linguistic distinctive features can be extracted and marked from the speech signal. These acoustic cues can be used to infer the intended underlying phoneme sequence in an utterance. This study describes a framework for labeling acoustic cues in speech, including a suite of canonical cue prediction algorithms that facilitates manual labeling and provides a standard for analyzing variations in the surface realizations. A brief examination of subsets of annotated speech data shows that labeling acoustic cues opens the possibility of detailed analyses of cue modification patterns in speech.

Irregular pitch periods (IPPs) are associated with grammatically, pragmatically, and clinically significant types of nonmodal phonation, but are challenging to identify. Automatic detection of IPPs is desirable because accurately hand-identifying IPPs is time-consuming and requires training. The authors evaluated an algorithm developed for creaky voice analysis to automatically identify IPPs in recordings of American English conversational speech. To determine a perceptually relevant threshold probability, frame-by-frame creak probabilities were compared to hand labels, yielding a threshold of approximately 0.02. These results indicate a generally good agreement between hand-labeled IPPs and automatic detection, calling for future work investigating effects of linguistic and prosodic context.

In the process of phonological development, fricatives are generally assumed to be later acquired than stops. However, most of the observational work on which this claim is based has concerned itself with word-initial onset consonants; little is known about how and when fricatives are mastered in word-final coda position (e.g., nose). This is all the more critical in a language like English, where word-final fricatives often carry important morphological information (e.g., toes, goes). This study examines the development of duration cues to the voicing feature contrast in coda fricatives, using longitudinal spontaneous speech data from CVC words (e.g., noise vs face) produced by three children (1;6-2;6 years) and six mothers. Results show that the children were remarkably adult-like in the use of duration cues to voicing contrasts in fricatives even in this early age range. Furthermore the children, like the mothers, had longer frication noise durations for morphemic compared to non-morphemic fricatives (e.g., toes vs nose) when these segments occurred in utterance-final position. These results suggest that although children's fricatives tend to be overall longer and more voiced compared to those of adults, the voicing and morphological contrasts for fricative codas are acquired early in production.

Research on children's speech perception and production suggests that consonant voicing and place contrasts may be acquired early in life, at least in word-onset position. However, little is known about the development of the acoustic correlates of later-acquired, word-final coda contrasts. This is of particular interest in languages like English where many grammatical morphemes are realized as codas. This study therefore examined how various non-spectral acoustic cues vary as a function of stop coda voicing (voiced vs. voiceless) and place (alveolar vs. velar) in the spontaneous speech of 6 American-English-speaking mother-child dyads. The results indicate that children as young as 1;6 exhibited many adult-like acoustic cues to voicing and place contrasts, including longer vowels and more frequent use of voice bar with voiced codas, and a greater number of bursts and longer post-release noise for velar codas. However, 1;6-year-olds overall exhibited longer durations and more frequent occurrence of these cues compared to mothers, with decreasing values by 2;6. Thus, English-speaking 1;6-year-olds already exhibit adult-like use of some of the cues to coda voicing and place, though implementation is not yet fully adult-like. Physiological and contextual correlates of these findings are discussed.

Numerous studies have indicated that prosodic phrase boundaries may be marked by a variety of acoustic phenomena including segmental lengthening. It has not been established, however, whether this lengthening is restricted to the immediate vicinity of the boundary, or if it extends over some larger region. In this study, segmental lengthening in the vicinity of prosodic boundaries is examined and found to be restricted to the rhyme of the syllable preceding the boundary. By using a normalized measure of segmental lengthening, and by compensating for differences in speaking rate, it is also shown that at least four distinct types of boundaries can be distinguished on the basis of this lengthening.