This study, which traces a hidden period in the history of linguistic sciences, reveals an important part of the ‘missing link’ between al-Zamakhshari and al-Sakkāqī for nearly a century. In this context, Fakhr al-Dīn al-Rāzī’s encyclopedic work Jāmi’u’l-‘ulūm is a noteworthy work that serves as a bridge between the two great scholars. Al-Rāzī went beyond Zamakhsharī’s aim to mention only the names of linguistic sciences and apply them in his tafsīr by focusing on the concepts, scope, and controversial issues of these sciences. In this work, al-Rāzī dealt with eight linguistic sciences: grammar, spelling, al-tikiq, emsāl, prosody, rhyme, rhyme, subtleties of poetry and verse, and meānī. Analyzing the accumulated knowledge that had reached him, al-Rāzī’s ideas in the field of language and rhetoric significantly influenced the scholars after him. In addition to analyzing the existing Persian edited edition of Jāmiʿ al-ʿulūm, this study also highlights a noteworthy connection to the chronological gaps in the reading of the history of linguistic sciences.