This research studied the phonetic variation of the Manobo language spoken in Surigao del Sur, Philippines using Foulkes Sociophonetic Variation Theory based on the notion that geographical and social background are sources of phonological variability. Geolinguistics as an approach was used as bases for examining sound patterns of the Manobo language used between two Manobo tribal communities, which are geographically distanced from each other. In-depth interviews using a stimulus material with 12 cultural bearers were conducted to collect linguistic samples. Findings of the segmental analysis revealed that the Manobo language spoken in the province is comprised of 19 consonants / b d k g h z ʤ ʒ ɭ m n ŋ ɼ ps t w j ʔ /, 10 vowels / a ɛ e æ i ɪ o u ʊ ə /, and four diphthongs / oʊ oɪ aɪ ʊɪ /. However between the two study sites, the consonant , which has three phonetic realizations  [z ʤ ʒ], was found to be exclusive in Barangay Cabangahan, while the consonant /d/ was found as the variety used in Sitio Simuwao in the absence of . On the other hand, the suprasegmental features revealed that variation in duration or phone length resulted in vowel lengthening and gemination or consonant lengthening, which were also found as determinants of sociophonetic variation. Manobo tribal communities in Surigao del Sur and IP-related agencies can use findings of this study in curricular and cultural planning for the continuous learning, documentation, and protection the linguistic diversity of the Manobo language.