Lingual and Acoustic Differences in EWE Oral and Nasal Vowels

It is an evidence that the production of nasal vowels involves not only the opening of the velopharyngeal port but also the lingual gesture variation. We tested the hypothesis that EWE speakers adjust tongue height to enhance the change in F1 due to the nasalization, by investigating simultaneously the physical configuration of the tongue and the acoustic output. It was found that EWE nasal vowels are produced with a higher and more forward tongue position than their oral counterparts, except /ẽ/ produced with a more retracted tongue position, and /õ/ produced with a lower and more retracted tongue position. We concluded that the lingual configuration of EWE nasal vowels differs from that of their oral congeners, enhancing the effect of the velum lowering on nasal vowels. Nevertheless, from the results, we suggested that the acoustic effects of nasalization on formants would not only depend on the adjustment of the tongue but a combination of multiples articulators.