The present study is a descriptive analysis of the morphosyntactic configuration of the native voseo of San Diego in the department of Cesar, population located in the Colombian Caribbean region. The research was developed through the analysis of speech samples collected in situations and spontaneous communicative events between locals and allowed the unveiling of the existence of the diphthongized voseo in the Valle del Cesar area, in addition to identifying the most distinctive characteristics of the voseo of San Diego (Cesar). This study responds to questions that have seen with little precision isogloss of Colombian voseo.