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Co-speech gestures are timed to occur with prosodically prominent syllables in several languages. In prior work in Indo-European languages, gestures are found to be attracted to stressed syllables, with gesture apexes preferentially aligning with syllables bearing higher and more dynamic pitch accents. Little research has examined the temporal alignment of co-speech gestures in African tonal languages, where metrical prominence is often hard to identify due to a lack of canonical stress correlates, and where a key function of pitch is in distinguishing between words, rather than marking intonational prominence. Here, we examine the alignment of co-speech gestures in two different Niger-Congo languages with very different word structures, Medʉmba (Grassfields Bantu, Cameroon) and Igbo (Igboid, Nigeria). Our findings suggest that the initial position in the stem tends to attract gestures in Medʉmba, while the final syllable in the word is the default position for gesture alignment in Igbo; phrase position also influences gesture alignment, but in language-specific ways. Though neither language showed strong evidence of elevated prominence of any individual tone value, gesture patterning in Igbo suggests that metrical structure at the level of the tonal foot is relevant to the speech-gesture relationship. Our results demonstrate how the speech-gesture relationship can be a window into patterns of word- and phrase-level prosody cross-linguistically. They also show that the relationship between gesture and tone (and the related notion of ‘tonal prominence’) is mediated by tone’s function in a language.
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Simultaneous acquisition of multiple auditory-motor transformations reveals supra-syllabic motor planning in speech production
Motor planning forms a critical bridge between psycholinguistic and motoric models of word production. While syllables are often considered the core planning unit in speech, growing evidence hints at supra-syllabic planning, but without firm empirical support. Here, we use differential adaptation to altered auditory feedback to provide novel, straightforward evidence for word-level planning. By introducing opposing perturbations to shared segmental content (e.g., raising the first vowel formant of “sev” in “seven” while lowering it in “sever”), we assess whether participants can use the larger word context to separately oppose the two perturbations. Critically, limb control research shows that such differential learning is possible only when the shared movement forms part of separate motor plans. We found differential adaptation in multisyllabic words, but of smaller size relative to monosyllabic words. These results strongly suggest speech relies on an interactive motor planning process encompassing both syllables and words.
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- Award ID(s):
- 2120506
- PAR ID:
- 10520581
- Publisher / Repository:
- OSF
- Date Published:
- Edition / Version:
- 5
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Posted Content:
- https://doi.org/10.31234/osf.io/ceqan
