Korebaju (ISO 639-3 coe) [ḱóˀrèbàjɨ ] is an endangered Tukanoan language spoken in the foothills of the Colombian Amazon. Two fieldworks carried out between 2021 and 2023 on a sample of 24 native speakers (12 females and 12 males) from two different varieties: Tama and Korebaju, located in two different villages, provide new data for improving intra-and inter-dialectal phonetic-phonological description of Korebaju. This acoustic study focuses on the vowel system of each of these two varieties and is the first part of an ongoing project on vowel nasalization and glottalization in Korebaju. The acoustic and statistical analyses indicate that there are no significant interdialectal differences between vowels. However, differences between generations of the same sex and of the same variety have been evidenced in our analyses. These results also suggest that Korebaju speakers' perception of stronger glottalization in the Tama variant refers to a morphological distinction. However, this hypothesis is still being analyzed considering the language's tonal system, nasalization, and morphology.