The study analysed spectral and tongue shape dynamics of voiceless alveolar and postalveolar fricatives produced by ten children learning Scottish English. Synchronised ultrasound tongue imaging data and acoustic data were used to characterise children's productions of the phonemic contrast. Six children had consistently accurate productions of both fricative targets, with some cross-consonant phonetic differences in the direction previously demonstrated for older children and adults, as well as some immature acoustic and articulatory dynamic patterns. Instrumental analyses made it possible to describe tongue shape for phonemic errors and phonetically distorted realisations. There was some evidence of articulatory contrast in production preceding contrast in perception. The observed patterns can be explained by the complex articulatory demands on the fricative production, in combination with the developing control of articulators. The paper concludes by discussing the implications of the results for phonological theory and for speech therapy practice.

中文翻译：

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三岁儿童清音摩擦音对比的发展：超声和声学研究

该研究分析了十名学习苏格兰英语的儿童所产生的清音齿槽擦音和齿槽后擦音的频谱和舌形动态。同步超声舌成像数据和声学数据用于表征儿童音位对比的产生。六名儿童始终准确地产生两个摩擦目标，在先前为大龄儿童和成人展示的方向上存在一些交叉辅音语音差异，以及一些不成熟的声学和发音动态模式。仪器分析使描述音位错误和语音失真实现的舌头形状成为可能。有一些证据表明生产中的发音对比先于感知对比。观察到的模式可以通过摩擦音产生的复杂发音要求以及发音器官的发展控制来解释。本文最后讨论了结果对语音理论和言语治疗实践的影响。