Background: The influence of the occlusal class in speech production has been studied using the X-ray Microbeam Speech Production Database (XRMB-SPD). Objectives/aims: This study aimed to relate the occlusal classes I and II with speech production adaptations. Methods: The Modified A-Space method was used to select 4 speakers (1 male and 1 female class I, 1 male and 1 female class II). Articulatory and acoustic features of the vowels were studied using different tasks and methods. The articulatory and acoustic features of consonants in male and female speakers of class I and class II from the XRMB-SPD were also described in detail. Measures extracted from multitaper spectra and articulatory data were used, to observe individual differences related with gender and dental occlusion. Results: Results showed some structural differences related to occlusal class and variance in class II subjects’ structures and articulatory adaptations. However, subjects showed a high adaptation capacity, being able to adjust their articulations to produce all vowels. Conclusions: Speech production variability is related with orofacial structures’ variance. Different structures produce various functional adaptations and distinct speech signals.