Previous studies on different languages and speech styles have shown that hesitation markers, like lengthenings and fillers, are characterized by specific pitch features. Typically, a flat pitch contour distinguishes hesitant prolongations from non-disfluent ones, the latter being realized with a higher pitch range and rising contour [1, 2]. Similarly, filled pauses were reported as occurring with low and flat or falling contour relative to the adjacent prosodic context [3, 4, 5]. However, while [1] found the plateau realization to be associated with filled pauses perceived as “felicitous”, and the falling contour with “infelicitous” instances, [6] showed that falling or rising contours systematically serve as a turn-holding device in dialogues. Also, in recent work on Italian discourse, pitch shape was observed as a relevant cue for discriminating lexical fillers (flat contour) from other discourse markers acting as rhetoric devices (peak contour) [7]. Our study further investigates the pitch characteristics of different hesitation types in Italian discourse, to find out whether phonetic differentiation reflects different communicative functions. Our analysis is based on a dataset from the C.H.R.O.M.E. corpus [8], consisting of 80 minutes of semi-spontaneous speech by three female expert tourist guides. Hesitations were defined as “content-free” material conveying procedural meaning in context; specifically, three types were considered: Lengthenings (as in “nell Certosa”), Filled Pauses (“ehm”, “eeh”), and Lexicalized Filled Pauses (“let’s say”, …). They were annotated along with their possible function/s according to their co-text: Hesitative, Word Searching, Structuring, Focusing (annotation scheme developed after [5]). Inter-annotator agreement yielded a Cohen’s kappa score of 0.73 [9]. Three phonetic parameters were considered: pitch contour shape (Flat, Falling, Rising, or Peak); pitch range (ST); distance (ST) between the pitch means of the hesitation and its corresponding intonational unit. For statistical analysis, Generalized Linear and Linear Mixed Models were fitted, each with one of the phonetic parameters as the dependent variable, hesitations’ “type” and “function” as interacting independent variables, and “speaker” and “item” as random intercepts, yielding the following significant results. Among the 975 instances, flat and peak pitch contours are the most frequent realizations (Fig. 1a, flat=65%; peak=30%). The flat contour is predominant in lengthenings and filled pauses, whereas peak contours only occur with lexical fillers. A visual inspection shows that “pitch contour” distinguishes lexical fillers having also a Structuring or Focusing function (Fig. 1.b). Especially fillers with a Focusing function occur more frequently with a peak profile (69%) than Word Searching (10%) and Hesitative (12%) ones, the latter being characterized by a flat profile. Though varying, pitch range was found to be affected by hesitation types and functions (Tab.1). Lengthenings mostly have a narrower range than fillers, while filled pauses involved in lexical retrieval generally occur with a wider range than the ones revealing general hesitation. Among lexical fillers, a wider range characterizes Focusing or Structuring. Also, including pitch contour as a fixed effect in the model shows that those with peak shape (9.31 ST) present a significantly wider range than flat ones (5.42 ST). As for the distance between hesitations and their surroundings, lengthenings, filled pauses, and lexicalized filled pauses all typically occur with lower pitch and are differentiated further by their functions: Hesitations revealing Word Searching function tend to be more phonetically distant from context than others, thereby “standing out”, whereas hesitations with a Focusing function do not. These results contribute to unveil the role of pitch in discriminating further communicative functions that hesitations may convey in Italian discourse. They may also provide interesting findings for technological applications striving towards better communicative efficiency and naturalness via integration of hesitations.

Pitch and Functional Characterization of Hesitation Phenomena in Italian Discourse

Loredana Schettino
Writing – Original Draft Preparation
;
Francesco Cutugno
Supervision
;
2021-01-01

Abstract

Previous studies on different languages and speech styles have shown that hesitation markers, like lengthenings and fillers, are characterized by specific pitch features. Typically, a flat pitch contour distinguishes hesitant prolongations from non-disfluent ones, the latter being realized with a higher pitch range and rising contour [1, 2]. Similarly, filled pauses were reported as occurring with low and flat or falling contour relative to the adjacent prosodic context [3, 4, 5]. However, while [1] found the plateau realization to be associated with filled pauses perceived as “felicitous”, and the falling contour with “infelicitous” instances, [6] showed that falling or rising contours systematically serve as a turn-holding device in dialogues. Also, in recent work on Italian discourse, pitch shape was observed as a relevant cue for discriminating lexical fillers (flat contour) from other discourse markers acting as rhetoric devices (peak contour) [7]. Our study further investigates the pitch characteristics of different hesitation types in Italian discourse, to find out whether phonetic differentiation reflects different communicative functions. Our analysis is based on a dataset from the C.H.R.O.M.E. corpus [8], consisting of 80 minutes of semi-spontaneous speech by three female expert tourist guides. Hesitations were defined as “content-free” material conveying procedural meaning in context; specifically, three types were considered: Lengthenings (as in “nell Certosa”), Filled Pauses (“ehm”, “eeh”), and Lexicalized Filled Pauses (“let’s say”, …). They were annotated along with their possible function/s according to their co-text: Hesitative, Word Searching, Structuring, Focusing (annotation scheme developed after [5]). Inter-annotator agreement yielded a Cohen’s kappa score of 0.73 [9]. Three phonetic parameters were considered: pitch contour shape (Flat, Falling, Rising, or Peak); pitch range (ST); distance (ST) between the pitch means of the hesitation and its corresponding intonational unit. For statistical analysis, Generalized Linear and Linear Mixed Models were fitted, each with one of the phonetic parameters as the dependent variable, hesitations’ “type” and “function” as interacting independent variables, and “speaker” and “item” as random intercepts, yielding the following significant results. Among the 975 instances, flat and peak pitch contours are the most frequent realizations (Fig. 1a, flat=65%; peak=30%). The flat contour is predominant in lengthenings and filled pauses, whereas peak contours only occur with lexical fillers. A visual inspection shows that “pitch contour” distinguishes lexical fillers having also a Structuring or Focusing function (Fig. 1.b). Especially fillers with a Focusing function occur more frequently with a peak profile (69%) than Word Searching (10%) and Hesitative (12%) ones, the latter being characterized by a flat profile. Though varying, pitch range was found to be affected by hesitation types and functions (Tab.1). Lengthenings mostly have a narrower range than fillers, while filled pauses involved in lexical retrieval generally occur with a wider range than the ones revealing general hesitation. Among lexical fillers, a wider range characterizes Focusing or Structuring. Also, including pitch contour as a fixed effect in the model shows that those with peak shape (9.31 ST) present a significantly wider range than flat ones (5.42 ST). As for the distance between hesitations and their surroundings, lengthenings, filled pauses, and lexicalized filled pauses all typically occur with lower pitch and are differentiated further by their functions: Hesitations revealing Word Searching function tend to be more phonetically distant from context than others, thereby “standing out”, whereas hesitations with a Focusing function do not. These results contribute to unveil the role of pitch in discriminating further communicative functions that hesitations may convey in Italian discourse. They may also provide interesting findings for technological applications striving towards better communicative efficiency and naturalness via integration of hesitations.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11386/4771304
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