Department of Linguistics, University of British Columbia, Vancouver, BC, Canada.
Department of Linguistics, University of California, Los Angeles, CA, USA.
Phonetica. 2023 Mar 29;79(6):523-549. doi: 10.1515/phon-2022-0001. Print 2022 Dec 16.
Lateral tongue bracing is a lingual posture in which the sides of the tongue are held against the palate and upper molars, and has been observed cross-linguistically. However, it is unknown whether lateral bracing makes adjustments to external perturbation like other body postures. The present study aims to test the robustness of lateral tongue bracing with three experiments. The first baseline experiment was an analysis of an electropalatogram database and the results showed lateral bracing being continuously maintained. The second experiment applied an external perturbation during speech production. A bite block was held between participants' teeth while intra-oral video was used to record contact between the sides of the tongue and upper molars during speech. The results indicated that lateral bracing was maintained most of the time during speech. The third experiment included simulations investigating the activation of tongue muscles relevant to lateral bracing at different degrees of jaw opening. The results show that bracing requires higher activation of bracing agonists and lower activation of bracing antagonists as jaw opening increases. Our results suggest that lateral tongue bracing is actively maintained and robust under external perturbation and further indicate it serves as an essential lingual posture during speech production.
舌侧支撑是一种舌位，其中舌的两侧抵在上颚和上颌磨牙上，这种舌位在不同语言中都有观察到。然而，目前还不清楚舌侧支撑是否像其他身体姿势一样对外部干扰做出调整。本研究旨在通过三个实验来测试舌侧支撑的稳健性。第一个基线实验是对一个电腭图数据库的分析，结果显示舌侧支撑持续保持。第二个实验在言语产生过程中施加外部干扰。在参与者的牙齿之间放置一个咬块，同时使用口腔内视频记录言语过程中舌的两侧与上颌磨牙之间的接触。结果表明，在大多数时间内，舌侧支撑在言语过程中都得到了维持。第三个实验包括模拟实验，研究了在不同程度的下颌开口时与舌侧支撑相关的舌肌的激活情况。结果表明，随着下颌开口的增加，支撑需要更高的支撑激动剂的激活和更低的支撑拮抗剂的激活。我们的研究结果表明，舌侧支撑在外部干扰下是主动维持的且稳健的，进一步表明它在言语产生过程中是一种基本的舌位。
