Disambiguation of ditropic sentences: acoustic and phonetic cues

In a previous study, we demonstrated that listeners were highly successful in identifying the intended meaning of spoken ditropic sentences (those which may carry either a literal or an idiomatic meaning) when speakers were instructed to convey the distinction. The present communication reports on acoustic and phonetic analyses carried out with the goal of identifying cues that distinguished the literal and idiomatic utterances. Certain prosodic differences were observed. Literal utterances were systematically longer than idioms. This was partly due to increased use of pauses, as well as to increased duration of major lexical items. Moreover, literal sentences were typically characterized by greater numbers of pitch contours (discernible rise-fall excursions of fundamental frequency) and open junctures than were idiomatic utterances. In addition to suprasegmental contrasts, articulatory distinctions--corresponding to lento-allegro phonological rules--were also observed. These distinctions directly reflect the structural differences intrinsic to the two types of utterances. A literal sentence is formulated by the organization of constituent words and phrases. Idioms, on the other hand, are holistic units, largely nontransparent to syntactic structure or the usual meaning of the lexical members.