Abstract：
Formants, or resonance frequencies of the upper vocal tract, are an essential part of acoustic communication. Articulatory gestures-such as jaw, tongue, lip, and soft palate movements-shape formant structure in human vocalizations, but little is known about how nonhuman mammals use those gestures to modify formant frequencies. Here, we report a case study with an adult male harbor seal trained to produce an arbitrary vocalization composed of multiple repetitions of the sound wa. We analyzed jaw movements frame-by-frame and matched them to the tracked formant modulation in the corresponding vocalizations. We found that the jaw opening angle was strongly correlated with the first (F1) and, to a lesser degree, with the second formant (F2). F2 variation was better explained by the jaw angle opening when the seal was lying on his back rather than on the belly, which might derive from soft tissue displacement due to gravity. These results show that harbor seals share some common articulatory traits with humans, where the F1 depends more on the jaw position than F2. We propose further in vivo investigations of seals to further test the role of the tongue on formant modulation in mammalian sound production.
摘要：
Formants,或上声带的共振频率，是声学通信的重要组成部分。发音手势——比如下巴，舌头,唇,人类发声中的软腭运动形成共振峰结构，但是人们对非人类哺乳动物如何使用这些手势来改变共振峰频率知之甚少。这里,我们报告了一个案例研究，该案例研究涉及成年雄性海豹，该海豹受过训练，可以产生由声音wa的多次重复组成的任意发声。我们逐帧分析了下颌运动，并将其与相应发声中的跟踪共振峰调制相匹配。我们发现，下颌张开角与第一个（F1）和，在较小程度上，与第二共振峰(F2)。F2变化更好地解释了当海豹躺在他的背上而不是腹部时，下巴角度打开，这可能是由于重力引起的软组织位移。这些结果表明，海豹与人类有一些共同的关节特征，其中F1比F2更依赖于钳口位置。我们建议对海豹进行进一步的体内研究，以进一步测试舌头在哺乳动物声音产生中对共振峰调制的作用。
