Contact is often cited as an explanation for the convergence of areal features and has been proposed as an explanation for the emergence of tonal languages in Mainland Southeast Asia. The current production study probes this hypothesis by exploring the relationship between tonal language usage and the acoustic correlates of the register distinction in Kuy, a Katuic language, as spoken in a quadrilingual (Kuy, Thai, Lao, Khmer) Kuy community in Northeast Thailand. The results demonstrate greater persistence of fundamental frequency (f0) differences over the course of the vowel alongside more tonal language experience for male speakers; however, analysis of individual differences finds that H1*−H2*, a correlate of voice quality, is the primary cue for male speakers with greater tonal language experience. For female speakers, a tradeoff is found between f0 and voice quality cues alongside tonal language experience at both the group and individual levels. These findings provide evidence for a model by which contact may serve to enhance existing, non-primary cues in a phonological contrast by shifting cue distributions, thereby increasing the likelihood that these cues will come to be perceived as prominent and phonologized.