In bilingual literature, few studies have examined the processes of concept formation (CF); even fewer studies have discussed their developmental changes. This study explores language-cognition links and CF fractionation processes by comparing total and partial immersion programmes (TIPs and PIPs). Descriptive statistics (DS), correlational analysis (CA) and principal component analysis (PCA) are performed to investigate language-cognition relationships and similarities and differences in developmental aspects between TIPs and PIPs. The DS and CA for PIPs demonstrate varying inter-individual differences depending on the courses and programmes. Moreover, despite the nearly equal ratio in the two languages used for the courses at the PIPs, the PCA results exhibit componential fractionations and time-sequential (developmental) changes similar to those for TIPs, suggesting unique language-cognition links. On one hand, the results for the two PIPs revealed a unique composition depending on the IP, and on the other hand, the extracted components mediated by the two languages demonstrated a similar developmental pattern. The findings for PIPs, since they share common CF characteristics with TIPs, imply that the instructional and developmental significance of the CF process transcends time and educational systems. In particular, the fractionation and diversification processes of components cannot be accounted for within a constrained framework of independent model in existing research on bilingual education. Based on the statistical outcomes, an interactive/developmental model may be a more viable alternative educational model.