Speech nasalization is achieved primarily through the opening and closing of the velopharyngeal port. However, the resultant acoustic features can also be influenced by tongue configuration. Although vowel nasalization is not contrastive in English, two previous studies have found possible differences in the oral articulation of nasal and oral vowel productions, albeit with inconsistent results. In an attempt to further understand the conflicting findings, we evaluated the oral kinematics of nasalized and non-nasalized vowels in a cohort of both male and female American English speakers via electromagnetic articulography. Tongue body and lip positions were captured during vowels produced in nasal and oral contexts (e.g., /mɑm/, /bɑb/). Large contrasts were seen in all participants between tongue position of /æ/ in oral and nasal contexts, in which tongue positions were higher and more forward during /mæm/ than /bæb/. Lip aperture was smaller in a nasal context for /æ/. Lip protrusion was not different between vowels in oral and nasal contexts. Smaller contrasts in tongue and lip position were seen for vowels /ɑ, i, u/; this is consistent with biomechanical accounts of vowel production that suggest that /i, u/ are particularly constrained, whereas /æ/ has fewer biomechanical constraints, allowing for more flexibility for articulatory differences in different contexts. Thus we conclude that speakers of American English do indeed use different oral configurations for vowels that are in nasal and oral contexts, despite vowel nasalization being non-contrastive. This effect was consistent across speakers for only one vowel, perhaps accounting for previously-conflicting results.

言语鼻化主要通过腭咽口的打开和关闭来实现。然而，最终的声学特征也会受到舌头构造的影响。尽管元音鼻化在英语中并不具有对比性，但之前的两项研究发现鼻元音和口腔元音的发音可能存在差异，尽管结果不一致。为了进一步理解相互矛盾的发现，我们通过电磁发音描记术评估了一组美国英语男性和女性的鼻化元音和非鼻化元音的口腔运动学。在鼻腔和口腔环境中发出元音时捕获舌体和嘴唇的位置（例如，/mɑm/、/bɑb/）。在所有参与者中，在口腔和鼻腔环境中 /æ/ 的舌头位置之间都存在很大的对比，其中 /mæm/ 期间的舌头位置比 /bæb/ 期间更高且更靠前。对于 /æ/，在鼻腔环境中唇部孔径较小。在口语和鼻语中，元音之间的唇部突出没有差异。对于元音/ɑ、i、u/，舌头和嘴唇位置的对比度较小；这与元音产生的生物力学解释一致，表明 /i、u/ 特别受到限制，而 /æ/ 的生物力学限制较少，从而可以更灵活地处理不同环境中的发音差异。因此，我们得出的结论是，尽管元音鼻化是非对比性的，但美式英语的使用者确实对鼻音和口语中的元音使用了不同的口语结构。这种效应在只有一个元音的说话者中是一致的，这或许可以解释之前相互矛盾的结果。