Mastery of expository text construction is a major expectation of all formal educational environments. These texts approach the discussion of topics from a detached stance, with limited intervention of specific participants and avoiding markers of personal involvement. Speakers/writers need to learn that such detachment constitutes a feature of the expository genre, as well as the particular way in which their language encodes the various means for (down)grading agency. We report two studies that aimed to explore the development of a detached stance in the expository genre from a cross-linguistic perspective. Study 1 examined the productive linguistic resources used by 70 (Iberian) Spanish monolingual and 67 Catalan/Spanish bilingual participants for expressing degrees of detachment in expository texts (N = 137) at different ages/schooling levels (grade school, junior-high, high-school, and university). Study 2 examined the off-line preferences of 62 Spanish-monolingual and 62 Spanish/Catalan bilingual participants (N = 124) at grade school, junior-high, and high-school in a preference judgment task. Production results (Study 1) showed that participants across age-groups and languages used linguistic options that fit the detachment requirements of expository texts. However, younger participants used phrase-level (local) detachment devices to a larger extent than those involving a rearrangement of argument structure (non-local devices), which showed a protracted development. This age effect was moderated by the modality of text production: Non-local devices were more typical of written texts. Language differences revealed a more detached stance in Catalan than in Spanish. Preference-judgment data (Study 2) revealed that younger participants more readily accept non-local devices as the most suitable choice for expository text construction. The complementary results from production and judgment data point at fundamental differences between language use and language awareness with regard to the demands of the expository genre.