Lexical stress information modulates the time-course of spoken-word recognition

Segmental as well as suprasegmental information is used by Dutch listeners to recognize words. The time-course of the effect of suprasegmental stress information on spoken-word recognition was investigated in a previous study, in which we tracked Dutch listeners' looks to arrays of four printed words as they listened to spoken sentences. Each target was displayed along with a competitor that did not differ segmentally in its first two syllables but differed in stress placement (e.g., 'CENtimeter' and 'sentiMENT'). The listeners' eye-movements showed that stress information is used to recognize the target before distinct segmental information is available. Here, we examine the role of durational information in this effect. Two experiments showed that initial-syllable duration, as a cue to lexical stress, is not interpreted dependent on the speaking rate of the preceding carrier sentence. This still held when other stress cues like pitch and amplitude were removed. Rather, the speaking rate of the preceding carrier affected the speed of word recognition globally, even though the rate of the target itself was not altered. Stress information modulated lexical competition, but did so independently of the rate of the preceding carrier, even if duration was the only stress cue present

The uptake of spectral and temporal cues in vowel perception is rapidly influenced by context

Speech perception is dependent on auditory information within phonemes such as spectral or temporal cues. The perception of those cues, however, is affected by auditory information in surrounding context (e.g., a fast context sentence can make a target vowel sound subjectively longer). In a two-by-two design the current experiments investigated when these different factors influence vowel perception. Dutch listeners categorized minimal word pairs such as /tɑk/–/taːk/ (“branch”–“task”) embedded in a context sentence. Critically, the Dutch /ɑ/–/aː/ contrast is cued by spectral and temporal information. We varied the second formant (F2) frequencies and durations of the target vowels. Independently, we also varied the F2 and duration of all segments in the context sentence. The timecourse of cue uptake on the targets was measured in a printed-word eye-tracking paradigm. Results show that the uptake of spectral cues slightly precedes the uptake of temporal cues. Furthermore, acoustic manipulations of the context sentences influenced the uptake of cues in the target vowel immediately. That is, listeners did not need additional time to integrate spectral or temporal cues of a target sound with auditory information in the context. These findings argue for an early locus of contextual influences in speech perception