Quantitative research on the linguistic acculturation of sojourners in non-Western and multilingual social contexts remains scarce. Revising the Framework of Acculturation Variables (FAV), we propose a parsimonious model exploring the effect of acculturation conditions (trilingual language usage and perceived discrimination), orientations (social connectedness to mainstream and minority community), and outcome (psychological well-being). In particular, we examined the alternative paths enabled by non-local languages in the acculturation process, revealing the complexity of multidimensionality in trilingual linguistic acculturation. The findings highlight the crucial mediating role of acculturation orientation in the acculturation process. The effects of Cantonese, Mandarin, and English usage on the acculturation process of Mainland Chinese students in Hong Kong (N = 798) were examined.