Perceived Prosodic Boundaries and Their Phonetic Correlates

PERCEIVED PROSODIC BOUNDARIES AND THEIR PHONETIC CORRELATES Renk Collier; Jan Roelof de Pijper and A ngelien Sanderman Institute for Perception Research / IPO P.O. Box 513, 5600 MB Eindhoven, The Netherlands ABSTRACT This paper addresses two main questions: (a) Can listeners as- sign values of perceived boundary strength to the juncture between any two words? (b) If so, what is the relationship between these values and various (combinations of) suprasegmental features. Three speakers read a set of twenty utterances of varying length and complexity. A panel of nineteen listeners assigned boundary strength values to each of the 175 word boundaries in the material. Then the correlation was established between the variable strength of the perceived boundaries and three prosodic variables: melodic discontinuity, declination reset and pause. The results show that speakers may differ in their strategies of prosodic boundary marking and listeners agree in the perceptual weight they attribute to the prosodic cues. 1. INTRODUCTION Any two successive words may vary as to their syntactic or semantic cohesiveness. The latter is likely to be strong- er if the two words are part of the same linguistic con- stituent; conversely, the occurrence of a constituent boun- dary between words decreases their degree of cohesive- ness. For example, in the sentence "(the man) (is sitting) (in the chair)", any two words separated by round brack- ets are structurally farther apart than those within a pair of brackets. Speakers are capable of making the juncture between constituents audible by prosodic means: they may produce appropriate cues in terms of pause, pitch and duration parameters. Listeners, on the other hand, can make use of these cues to segment the incoming flow of speech into word sequences that may be treated as a whole, which facilitates the comprehension process. In certain cases, prosodic demarcation may help in resolving structural ambiguity, for instance in utterances of the type "The girl saw the man with the telescope", in which the prepositional phrase specifies either the verb or its direct object [1, 2]. But in utterances containing no surface syn- tactic homonymy, too, prosodic boundaries may delineate coherent word groups and lend support to the listener's hypotheses about syntactic-semantic structure as, for in- stance, in "the beautiful girl / with brown eyes / told her story / to the psychiatrist" [3]. This paper presents results of research that, starting from the observation that listeners do provide prosodic boun- dary cues, addresses two main questions: (a) Can listeners assign a value of Perceived Boundary Strength (PBS) to word boundaries? (b) If so, what is the relationship between PBS and dif- ferent (combinations of) suprasegmental features? The answer to these questions may lead to a better model of what prosodic resources a speaker can draw on to highlight the syntactic-semantic structure of an utterance. Such insight may, in turn, contribute to improved prosody in speech synthesis, by making it sound more natural and -more importantly- by making it linguistically more transparent and therefore easier to comprehend. This re- search may …

Content truncated to 500 words