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From: Fang-Chi Chou
Date: 13 Oct 2011
Time: 12:51:40 -0500
Remote Name: 129.255.231.57
Hi Heather, I am a doctoral student of Dr. Zebrowski. I summaried the results of my research. Hope the information will be helpful for you! My research examined the influence of Mandarin tones on stuttering loci in preschoolers. In English, stuttering occurs more on stressed words, which have high variability in speech production (longer duration, louder intensity, and more varied pitch movement). Individuals who stutter are vulnerable to increased variability, resulting in more speech disruptions in connected speech. In Mandarin, tone is one of the paramount characteristics. Every Mandarin syllable carries a tone. Changing the tone of a syllable can alter its meaning. There are five tones in Mandarin: four lexical tones (Tones 1, 2, 3, 4) and a neutral tone (Tone 5). The results of my research showed that stuttering occurred more on four lexical tones instead of on the neutral tone. The reason may be: the four lexical tones all have a distinctive pitch contour, while the neutral tone doesn’t have one. The pitch of the neutral tone depends on what the preceding tone is. Therefore, the syllables carry the neutral tone are generally defined as “toneless.” Second, compared to four lexical tones, the neutral tone is shorter and softer. The Mandarin neutral tone is somewhat comparable to English unstressed words. Thus, less stuttering instances were found in syllables carrying the neutral tone. Compared to the neutral tone, the four lexical tones have longer duration, louder intensity, and distinctive pitch contours. Mandarin lexical tones are somewhat comparable to English stressed words. Thus, stuttering instances were found more frequently on syllables on syllables with carrying four lexical tones. Among the four lexical tones, the research results showed that stuttering instances occurred more frequently on syllables carrying Tones 3 and 4. Compared to Tones 1 and 2, Tones 3 and 4 have higher production variability. The variability may come from production difficulty of the tone itself and the influence from the tonal context. (For example, the pitch contour of a tone can be changed in terms of what the preceding and following tones are). Tone 3 is a falling-rising tone. That is, when producing Tone 3, we lower the F0 first, and then raise the F0 at the second part. Tone 3 is the latest required because of having more variations in distinctive contours. That is, it can be produced as Tone 2 or half-Tone 3 (only the first falling part) depending on what the following tone is. The varied alternation in pitch target can contribute to high processing load, leading to more production variation. On the other hand, when producing Tone 4, we drop the F0 rapidly from the highest level of the pitch register to the lowest level of the pitch register. This dramatic pitch change can pose a challenge in speech motor system, causing more speech disruption. This study focused on investigating the relation between Mandarin tones and stuttering loci. However, linguistic factors that can influence stuttering loci are interdependent. We still have to consider other linguistic factors such as content vs. function words and word position. Like English, stuttering events are more likely to be found on: 1) content words for adults; 2) function words for preschoolers; 3) the initial position of a word, sentence, and utterance (Based on Yang’s research in 2002). The aforementioned research results are what we have known about stuttering loci in Mandarin. Definitely, more studies are needed! Fang-Chi