There is increasing evidence that, in addition to velopharyngeal coupling, lingual position may also change during production of phonemic nasal vowels. In order to investigate differences in oral articulation between European Portuguese (EP) nasal vowels and oral counterparts, imaging data (both static and real-time MRI) of several EP speakers (male and female) are used. Superimposition of outlines of the vocal tract profiles, semi-automatically extracted from MRI images, were used to compare the position of tongue and lips during nasal and oral vowel production. The results suggest that lingual and labial differences between nasal vowels and their oral counterparts are quite subtle in EP. Nasal vowels [ɐ~], [õ] exhibited more articulatory adjustments with respect to oral congeners than [i~] and [u~].

Index Terms: nasal vowels, Magnetic Resonance Imaging (MRI), European Portuguese