This study problematises the discourses of Pakistan's national curriculum textbooks to investigate how they represent Pakistan's indigenous languages/cultures through the prism of religion to constitute secondary school students' particular postcolonial linguistic identities. It also draws on the perspectives of 12 teachers and 424 students to record their responses. Taking insights from Paulo Freire's "cultural invasion," Robert Blauner's "internal colonisation" and selected postcolonial perspectives, the study notes a dynamic interplay of the sampled textbooks, schoolteachers and the school as a site of discursive social practices. Jointly, they position students within an exclusionary homogenous Urdu-loving group--a language which is represented as Arabic's tributary. Indigenous languages are recognised, however, as an adjunct to Arabic and Urdu, emphasising their role in the proselytisation of Islam in the region. Similarly, fine arts and indigenous cultural festivals are represented from a particular religious lens. The students strongly identify with this curious case of "internal colonisation" and "cultural invasion," and support it. They exhibit self-righteousness and aversion towards linguistic/cultural pluralism and minorities, which entails implications for Pakistan's national cohesion and educational parlance of equity and inclusivity.