This study examines the phonological status of the schwa vowel in Gilaki, a northwestern Iranian language spoken along the southern Caspian Sea. The status of this vowel has been a subject of scholarly debates. In the present research, a combination of phonological, acoustic, and etymological analyses was utilized to determine the status of this vowel in the phonological system of Gilaki. Schwa distribution has been analyzed across different phonetic environments, including word-initial, medial, and final positions. The findings revealed that schwa commonly arises from the centralization of ɑ, driven by coarticulatory effects of adjacent liquids (l, r) and nasals (n, m). This shift occurs in all phonetic contexts except when preceded by laryngeal consonants in word-initial positions. In this context, the change is inhibited due to these consonants’ place of articulation, which prevents them from affecting the formant frequencies of ɑ, thus preserving its original form. In addition, schwa serves an anaptyctic role in Gilaki, helping to break initial consonant clusters. It is worth noting that the insertion of this vowel to adjust syllable structures predetermines its inclusion in Gilaki’s vowel inventory. All in all, this study indicated that over time, some minor articulatory effects of consonants have led to an ongoing unconditioned change of ɑ toward ə.