North-Holland Word boundary cues in clear speech: A supplementary report

Abstract. One of a listener's major tasks in understanding continuous speech is segmenting the speech signal into separate words. When listening conditions are difficult, speakers can help listeners by deliberately speaking more clearly. In four experiments, we examined how word boundaries are produced in deliberately clear speech. In an earlier eport we showed that speakers do indeed mark word boundaries in clear speech, by pausing at the boundary and lengthening pre-boundary syllables: moreover, these effects are applied particularly to boundaries preceding weak syllables. In English, listeners use segmentation procedures which make word boundaries before strong syllables easier to perceive: thus marking word boun-daries before weak syllables in clear speech will make clear precisely those boundaries which are otherwise hard to perceive. The present report presents supplementary data, namely prosodic analyses of the syllable following a critical word boundary. More lengthening and greater increases in intensity were applied in clear speech to weak syllables than to strong. Mean F0 was also increased to a greater extent on weak syllables than on strong. Pitch movement, however, increased to a greater extent on strong syllables than on weak. The effects were, however, very small in comparison to the durational effects we observed earlier for syllables preceding the boundary and for pauses at the boundary. Zusammenfassung, Eine der Hauptaufgaben for den Herer beim Verstehen fliessender Sprache ist die Zerlegung des Sprachsignals in W{Srter. Wenn die Herbedingungen u giinstig sind, kann der Sprecber dem Zuh6rer dufch bewusst deut-liches Sprechen helfen. In vier Experimenten haben wir untersucht, wie Wortgrenzen i bewusst deutlich gesprochene