The Journal of Studies in Language 40.4, 499-510. This study examines the usage of the relative pronouns ‘who’, ‘which’, and ‘that’ in both written and spoken English, focusing on how context influences pronoun choice. Through a corpusbased analysis of 400 sentences―200 from formal written English and 200 from casual spoken English―the study identifies significant differences in pronoun usage across registers. The findings reveal that in formal written contexts, ‘who’ and ‘which’ are strongly preferred, reflecting a need for clarity and precision. In contrast, spoken English shows a greater reliance on ‘that’, particularly with inanimate antecedents, highlighting the greater versatile and concise nature of spoken language. Statistical analyses, including chi-square and binomial tests, were used to assess the significance of these differences. Additionally, Cramer’s V was calculated to measure the strength of association between context and pronoun choice. The results suggest a moderate association for ‘who’ vs. ‘that’ (Cramer’s V = 0.28) and a stronger association for ‘which’ vs. ‘that’ (Cramer’s V = 0.53), confirming that context plays a crucial role in relative pronoun selection. These findings have important implications for both linguistic theory and English language pedagogy, underscoring the need to teach context-sensitive grammar to learners.