Christophe, A., Gout, A., Peperkamp, S. & Morgan, J. (2003). Discovering words in the continuous speech stream: the role of prosody. Journal of Phonetics, 31, 585 – 598.
Presentation: Hsiao-chien
Summary: Shelly
Studies concerning word segmentation have found that allophonic cues, phonotactic rules, and stress patterns are used by both infants and adults for word boundary detection. However, whether cues from prosodic units play a role in this regard was less discussed. It was suggested that the coincidence of the target word boundary and an intonational phrase boundary can constrain the number of possible lexical activation triggered by the target word during on-line processing, which facilitates listeners to detect the target word at a faster speed. Therefore, this study intends to further the discussion on relevant issues by reviewing literatures exploring whether and how adults and infants benefit from prosodic boundary cues when trying to detect target words from sound sequences. Two experiments were reviewed. The first one was an experiment on French adults. They were asked to detect target words embedded in sentences as soon as possible. Results showed that for words which could be legally combined with the following syllable to form another words, detection was slower than those that could not. However, if an intonational phrase boundary was inserted inbetween the target word and the following syllable, the above differences between the two conditions disappeared and the listeners’ speed of detection became a lot faster. The results suggested that the existence of phrase boundaries indeed help on-line word segmentation. A similar experiment was done in another study on American infants, where word detection was observed through the head-turning paradigm. Results indicated the same patterns as those for the French adults in the first study. Results from the two studies suggested that phonological phrase boundaries are consistently used by human beings for word segmentation at a very early age. One of the possible causes may be that phonetic cues at phrase boundaries are usually strengthened, such as final lengthening, which amplifies the salience of the target words, resulting in faster detection by listeners. It was suggested that future studies would be needed to find out whether this is a universal pattern and what other boundary cues may be helpful in word segmentation, the results of which could be used to refine models for speech processing and language acquisition.
Studies concerning word segmentation have found that allophonic cues, phonotactic rules, and stress patterns are used by both infants and adults for word boundary detection. However, whether cues from prosodic units play a role in this regard was less discussed. It was suggested that the coincidence of the target word boundary and an intonational phrase boundary can constrain the number of possible lexical activation triggered by the target word during on-line processing, which facilitates listeners to detect the target word at a faster speed. Therefore, this study intends to further the discussion on relevant issues by reviewing literatures exploring whether and how adults and infants benefit from prosodic boundary cues when trying to detect target words from sound sequences. Two experiments were reviewed. The first one was an experiment on French adults. They were asked to detect target words embedded in sentences as soon as possible. Results showed that for words which could be legally combined with the following syllable to form another words, detection was slower than those that could not. However, if an intonational phrase boundary was inserted inbetween the target word and the following syllable, the above differences between the two conditions disappeared and the listeners’ speed of detection became a lot faster. The results suggested that the existence of phrase boundaries indeed help on-line word segmentation. A similar experiment was done in another study on American infants, where word detection was observed through the head-turning paradigm. Results indicated the same patterns as those for the French adults in the first study. Results from the two studies suggested that phonological phrase boundaries are consistently used by human beings for word segmentation at a very early age. One of the possible causes may be that phonetic cues at phrase boundaries are usually strengthened, such as final lengthening, which amplifies the salience of the target words, resulting in faster detection by listeners. It was suggested that future studies would be needed to find out whether this is a universal pattern and what other boundary cues may be helpful in word segmentation, the results of which could be used to refine models for speech processing and language acquisition.
