This study delves into Fakhr al-Dīn al-Rāzī's (1149–1210) theory of language, a pivotal yet underexplored facet of his intellectual legacy. Moving beyond his interactions with the Avicennian tradition, it positions al-Rāzī as an independent thinker. The work examines two often misinterpreted dimensions of his thought: his assertion that all concepts are self-evident, challenging traditional epistemology on conceptualization (taṣawwur) as advanced by Abū Naṣr al-Fārābī (870–950) and Ibn Sīnā (980–1037), and his refinement of ʿAbd-l-Qāhir al-Ğurğānī’s (1009–1078) theory of linguistic composition (naẓm), emphasizing language’s expressive capacity (bayān) and the Qurʾān’s unique linguistic structure. By analyzing these facets, the study reconstructs al-Rāzī’s comprehensive framework for understanding linguistic phenomena, bridging the Greek-inspired falsafa tradition and the rich Arabic linguistic heritage. This exploration offers scholars and students a nuanced perspective on Islamic intellectual history, highlighting al-Rāzī’s role in harmonizing diverse traditions and advancing a profound theory of linguistic understanding. This theory is essential for engaging with al-Rāzī’s extensive written heritage.