In this paper we address issues related to comprehension processes, and how they can be affected by types of text or written discourse, and by a reader’s first or second language. To this end, we discuss the processing of narrative and expository texts, and their effects on different levels of human cognition. Likewise, we discuss the effects of texts written in different codes, that is, in first and second languages. We propose that differences in text comprehension processes occur as a function of their causal nature and of the inferences that are generated during comprehension. In terms of second language comprehension, modern research applying functional magnetic resonance imaging, or fMRI, with bilinguals is discussed in support of the notion that first language comprehension processes are generally replicated in the second language. Therefore, we focus on comprehension processes, generation of interferences, and the processing of a second language as influenced by linguistic relativism.