The present study explores the production of English dental fricatives /θ/ and /e/ in L1 Portuguese, with a particular focus on this under-studied population whose legacy European Portuguese influences are increasingly flanked by more pronounced Brazilian varieties and strong Bantu influence within constant contact. In this paper, we report ongoing classroom-based action research aiming to identify patterns of substitution and effects of phonological context through both acoustic and perceptual analysis of recordings produced by 18 university learners taking English at Instituto Superior Politécnico de Cabinda (ISPC), Angola. The results indicate that /θ/ is predominantly realized as [f] (41.2%), followed by [s] (28.7%), whereas /e/ is most commonly realized as [d] (51.9%) and secondarily as [z] (26.9%). Word-final position shows the highest error rates. Acoustic measurements confirm that substitutions have a different spectral signature from native interdentals, with drastically different Center of Gravity values (Cohen’s d > 2.0). These acoustic differences indicate possible intelligibility effects, which will need to be directly tested for confirmation. The abundance of differences sustains the equivalence schema, favoring the familiar articulation. The results suggest pedagogical strategies such as explicit articulatory instruction, focused minimal pair training, and tailored curriculums for healthcare students.
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